fix: harden data integrity, connection stability, and memory management

Wrap all multi-write DB operations in atomic transactions (server/channel
creation, message+attachment linking, DM creation, friend acceptance,
cascading deletes) to prevent partial-write corruption.

Batch N+1 queries in WS ready payload into O(1) bulk fetches with
chunked inArray() to respect SQLite's variable limit.

Fix chat history regression where background WS messages bypassed
channel load by switching the guard from messages.has() to hasMore.has().

Add LRU channel eviction (20 cached, evict to 15) and per-channel
message cap (200) to bound client memory growth.

Shorten WS heartbeat from 30s to 15s for aggressive proxy/NAT
environments. Clear all user-scoped stores on logout to prevent
cross-session data leaks.

Extract LiveKit internal accessors into shared livekitInternals utility.

packages/server/src/routes/dm.ts

@@ -374,24 +374,26 @@ export async function dmRoutes(app: FastifyInstance): Promise<void> {
       }
     }
 
-    // Create new DM channel
+    // Create new DM channel with both members atomically
     const dmChannelId = generateSnowflake();
     const now = Date.now();
 
-    db.insert(schema.dmChannels).values({
-      id: dmChannelId,
-      createdAt: now,
-    }).run();
+    db.transaction((tx) => {
+      tx.insert(schema.dmChannels).values({
+        id: dmChannelId,
+        createdAt: now,
+      }).run();
 
-    db.insert(schema.dmMembers).values({
-      dmChannelId,
-      userId: request.userId,
-    }).run();
+      tx.insert(schema.dmMembers).values({
+        dmChannelId,
+        userId: request.userId,
+      }).run();
 
-    db.insert(schema.dmMembers).values({
-      dmChannelId,
-      userId,
-    }).run();
+      tx.insert(schema.dmMembers).values({
+        dmChannelId,
+        userId,
+      }).run();
+    });
 
     const currentUserRow = db.select().from(schema.users).where(eq(schema.users.id, request.userId)).get();
     const members = [currentUserRow, targetUser]
@@ -791,24 +793,26 @@ export async function dmRoutes(app: FastifyInstance): Promise<void> {
     const messageId = generateSnowflake();
     const now = Date.now();
 
-    db.insert(schema.dmMessages).values({
-      id: messageId,
-      dmChannelId: id,
-      userId: request.userId,
-      replyToId: replyToId || null,
-      content: content?.trim() || null,
-      createdAt: now,
-    }).run();
+    // Insert message and link attachments atomically
+    db.transaction((tx) => {
+      tx.insert(schema.dmMessages).values({
+        id: messageId,
+        dmChannelId: id,
+        userId: request.userId,
+        replyToId: replyToId || null,
+        content: content?.trim() || null,
+        createdAt: now,
+      }).run();
 
-    // Link attachments to this DM message
-    if (attachmentIds && attachmentIds.length > 0) {
-      for (const attId of attachmentIds) {
-        db.update(schema.attachments)
-          .set({ dmMessageId: messageId })
-          .where(eq(schema.attachments.id, attId))
-          .run();
+      if (attachmentIds && attachmentIds.length > 0) {
+        for (const attId of attachmentIds) {
+          tx.update(schema.attachments)
+            .set({ dmMessageId: messageId })
+            .where(eq(schema.attachments.id, attId))
+            .run();
+        }
       }
-    }
+    });
 
     const message = getDmMessageWithUser(messageId);
     if (!message) {
@@ -886,20 +890,20 @@ export async function dmRoutes(app: FastifyInstance): Promise<void> {
       return reply.code(403).send({ error: 'You can only delete your own messages', statusCode: 403 });
     }
 
-    // Delete attachments linked to this DM message
-    db.delete(schema.attachments)
-      .where(eq(schema.attachments.dmMessageId, id))
-      .run();
+    // Delete attachments, reactions, and message atomically
+    db.transaction((tx) => {
+      tx.delete(schema.attachments)
+        .where(eq(schema.attachments.dmMessageId, id))
+        .run();
 
-    // Delete reactions
-    db.delete(schema.dmReactions)
-      .where(eq(schema.dmReactions.dmMessageId, id))
-      .run();
+      tx.delete(schema.dmReactions)
+        .where(eq(schema.dmReactions.dmMessageId, id))
+        .run();
 
-    // Delete message
-    db.delete(schema.dmMessages)
-      .where(eq(schema.dmMessages.id, id))
-      .run();
+      tx.delete(schema.dmMessages)
+        .where(eq(schema.dmMessages.id, id))
+        .run();
+    });
 
     // Broadcast to all DM members
     const dmMembers = db.select()

packages/server/src/routes/messages.ts

@@ -274,24 +274,26 @@ export async function messageRoutes(app: FastifyInstance): Promise<void> {
     const messageId = generateSnowflake();
     const now = Date.now();
 
-    db.insert(schema.messages).values({
-      id: messageId,
-      channelId: id,
-      userId: request.userId,
-      replyToId: replyToId || null,
-      content: content?.trim() || null,
-      createdAt: now,
-    }).run();
+    // Insert message and link attachments atomically
+    db.transaction((tx) => {
+      tx.insert(schema.messages).values({
+        id: messageId,
+        channelId: id,
+        userId: request.userId,
+        replyToId: replyToId || null,
+        content: content?.trim() || null,
+        createdAt: now,
+      }).run();
 
-    // Link attachments to message
-    if (attachmentIds && attachmentIds.length > 0) {
-      for (const attId of attachmentIds) {
-        db.update(schema.attachments)
-          .set({ messageId })
-          .where(eq(schema.attachments.id, attId))
-          .run();
+      if (attachmentIds && attachmentIds.length > 0) {
+        for (const attId of attachmentIds) {
+          tx.update(schema.attachments)
+            .set({ messageId })
+            .where(eq(schema.attachments.id, attId))
+            .run();
+        }
       }
-    }
+    });
 
     const user = db.select().from(schema.users).where(eq(schema.users.id, request.userId)).get();
     if (!user) {
@@ -415,9 +417,11 @@ export async function messageRoutes(app: FastifyInstance): Promise<void> {
       return reply.code(403).send({ error: 'You cannot delete this message', statusCode: 403 });
     }
 
-    // Delete attachments then message
-    db.delete(schema.attachments).where(eq(schema.attachments.messageId, id)).run();
-    db.delete(schema.messages).where(eq(schema.messages.id, id)).run();
+    // Delete attachments and message atomically
+    db.transaction((tx) => {
+      tx.delete(schema.attachments).where(eq(schema.attachments.messageId, id)).run();
+      tx.delete(schema.messages).where(eq(schema.messages.id, id)).run();
+    });
 
     // Broadcast deletion
     connectionManager.sendToServer(serverId, {

packages/server/src/routes/servers.ts

@@ -80,33 +80,33 @@ export async function serverRoutes(app: FastifyInstance): Promise<void> {
     const now = Date.now();
     const inviteCode = generateInviteCode();
 
-    // Create the server
-    db.insert(schema.servers).values({
-      id: serverId,
-      name: trimmedName,
-      icon: icon ?? null,
-      ownerId: request.userId,
-      inviteCode,
-      createdAt: now,
-    }).run();
+    // Create server, owner membership, and default channel atomically
+    db.transaction((tx) => {
+      tx.insert(schema.servers).values({
+        id: serverId,
+        name: trimmedName,
+        icon: icon ?? null,
+        ownerId: request.userId,
+        inviteCode,
+        createdAt: now,
+      }).run();
 
-    // Add owner as member with 'owner' role
-    db.insert(schema.serverMembers).values({
-      serverId,
-      userId: request.userId,
-      role: 'owner',
-      joinedAt: now,
-    }).run();
+      tx.insert(schema.serverMembers).values({
+        serverId,
+        userId: request.userId,
+        role: 'owner',
+        joinedAt: now,
+      }).run();
 
-    // Create default #general text channel
-    db.insert(schema.channels).values({
-      id: channelId,
-      serverId,
-      name: 'general',
-      type: 'text',
-      position: 0,
-      createdAt: now,
-    }).run();
+      tx.insert(schema.channels).values({
+        id: channelId,
+        serverId,
+        name: 'general',
+        type: 'text',
+        position: 0,
+        createdAt: now,
+      }).run();
+    });
 
     const server = db.select().from(schema.servers).where(eq(schema.servers.id, serverId)).get();
     if (!server) {
@@ -302,10 +302,12 @@ export async function serverRoutes(app: FastifyInstance): Promise<void> {
       return reply.code(403).send({ error: 'Only the server owner can delete the server', statusCode: 403 });
     }
 
-    // Delete all channels (messages cascade), members, then server
-    db.delete(schema.channels).where(eq(schema.channels.serverId, id)).run();
-    db.delete(schema.serverMembers).where(eq(schema.serverMembers.serverId, id)).run();
-    db.delete(schema.servers).where(eq(schema.servers.id, id)).run();
+    // Delete all channels (messages cascade), members, then server atomically
+    db.transaction((tx) => {
+      tx.delete(schema.channels).where(eq(schema.channels.serverId, id)).run();
+      tx.delete(schema.serverMembers).where(eq(schema.serverMembers.serverId, id)).run();
+      tx.delete(schema.servers).where(eq(schema.servers.id, id)).run();
+    });
 
     return reply.code(200).send({ success: true });
   });

packages/server/src/routes/social.ts

@@ -207,15 +207,22 @@ export async function socialRoutes(app: FastifyInstance): Promise<void> {
     }
 
     if (status === 'accepted') {
-      // Add to friends table
+      // Insert friend and update request status atomically
       const now = Date.now();
-      db.insert(schema.friends).values({
-        userId: friendRequest.fromId,
-        friendId: friendRequest.toId,
-        createdAt: now,
-      }).run();
+      db.transaction((tx) => {
+        tx.insert(schema.friends).values({
+          userId: friendRequest.fromId,
+          friendId: friendRequest.toId,
+          createdAt: now,
+        }).run();
 
-      // Get the accepting user's data for the WS event
+        tx.update(schema.friendRequests)
+          .set({ status })
+          .where(eq(schema.friendRequests.id, id))
+          .run();
+      });
+
+      // WS broadcast AFTER transaction commits
       const acceptingUser = db.select().from(schema.users).where(eq(schema.users.id, request.userId)).get();
       if (acceptingUser) {
         const friend: Friend = {
@@ -228,14 +235,14 @@ export async function socialRoutes(app: FastifyInstance): Promise<void> {
           requestId: id,
         });
       }
+    } else {
+      // For declined, just update the status (single write, no transaction needed)
+      db.update(schema.friendRequests)
+        .set({ status })
+        .where(eq(schema.friendRequests.id, id))
+        .run();
     }
 
-    // Update request status
-    db.update(schema.friendRequests)
-      .set({ status })
-      .where(eq(schema.friendRequests.id, id))
-      .run();
-
     return reply.code(200).send({ success: true });
   });
 

packages/server/src/ws/handler.ts

@@ -2,7 +2,7 @@ import type { FastifyInstance } from 'fastify';
 import type { WebSocket } from 'ws';
 import { verifyJwt } from '../utils/auth.js';
 import { getDb, schema } from '../db/index.js';
-import { eq, inArray, desc } from 'drizzle-orm';
+import { eq, inArray, desc, sql } from 'drizzle-orm';
 import { handleClientEvent } from './events.js';
 import type {
   User,
@@ -16,6 +16,19 @@ import type {
   ActiveCallInfo,
 } from '@opencord/shared';
 
+// SQLite's SQLITE_MAX_VARIABLE_NUMBER default is 999.
+// Chunk inArray() calls to stay safely under this limit.
+const BATCH_CHUNK_SIZE = 500;
+
+function batchInArray<TId, TResult>(ids: TId[], queryFn: (chunk: TId[]) => TResult[]): TResult[] {
+  if (ids.length <= BATCH_CHUNK_SIZE) return queryFn(ids);
+  const results: TResult[] = [];
+  for (let i = 0; i < ids.length; i += BATCH_CHUNK_SIZE) {
+    results.push(...queryFn(ids.slice(i, i + BATCH_CHUNK_SIZE)));
+  }
+  return results;
+}
+
 function sanitizeUser(row: typeof schema.users.$inferSelect): User {
   return {
     id: row.id,
@@ -495,11 +508,36 @@ function buildReadyPayload(userId: string): {
       .where(inArray(schema.servers.id, serverIds))
       .all();
 
+    // Batch: all channels for all servers (1 query instead of N)
+    const allChannels = batchInArray(
+      serverIds,
+      ids => db.select().from(schema.channels).where(inArray(schema.channels.serverId, ids)).all(),
+    );
+    const channelsByServer = new Map<string, (typeof allChannels)>();
+    for (const ch of allChannels) {
+      let arr = channelsByServer.get(ch.serverId);
+      if (!arr) { arr = []; channelsByServer.set(ch.serverId, arr); }
+      arr.push(ch);
+    }
+
+    // Batch: last message ID per channel (1 query instead of N×C)
+    const allChannelIds = allChannels.map(ch => ch.id);
+    const lastMsgMap = new Map<string, string>();
+    if (allChannelIds.length > 0) {
+      const lastMsgRows = batchInArray(
+        allChannelIds,
+        ids => db.select({
+          channelId: schema.messages.channelId,
+          lastId: sql<string>`max(${schema.messages.id})`,
+        }).from(schema.messages).where(inArray(schema.messages.channelId, ids)).groupBy(schema.messages.channelId).all(),
+      );
+      for (const row of lastMsgRows) {
+        if (row.lastId) lastMsgMap.set(row.channelId, row.lastId);
+      }
+    }
+
     for (const serverRow of serverRows) {
-      const channels = db.select()
-        .from(schema.channels)
-        .where(eq(schema.channels.serverId, serverRow.id))
-        .all();
+      const channels = channelsByServer.get(serverRow.id) ?? [];
 
       const roles = db.select()
         .from(schema.roles)
@@ -514,7 +552,7 @@ function buildReadyPayload(userId: string): {
 
       const memberUserIds = memberRows.map(m => m.userId);
       const users = memberUserIds.length > 0
-        ? db.select().from(schema.users).where(inArray(schema.users.id, memberUserIds)).all()
+        ? batchInArray(memberUserIds, ids => db.select().from(schema.users).where(inArray(schema.users.id, ids)).all())
         : [];
       const userMap = new Map(users.map(u => [u.id, u]));
 
@@ -562,24 +600,16 @@ function buildReadyPayload(userId: string): {
         ownerId: serverRow.ownerId,
         inviteCode: serverRow.inviteCode,
         createdAt: serverRow.createdAt,
-        channels: channels.map(ch => {
-          const lastMsg = db.select({ id: schema.messages.id })
-            .from(schema.messages)
-            .where(eq(schema.messages.channelId, ch.id))
-            .orderBy(desc(schema.messages.createdAt))
-            .limit(1)
-            .get();
-          return {
-            id: ch.id,
-            serverId: ch.serverId,
-            name: ch.name,
-            type: ch.type as Channel['type'],
-            topic: ch.topic,
-            position: ch.position ?? 0,
-            createdAt: ch.createdAt,
-            lastMessageId: lastMsg?.id ?? null,
-          };
-        }),
+        channels: channels.map(ch => ({
+          id: ch.id,
+          serverId: ch.serverId,
+          name: ch.name,
+          type: ch.type as Channel['type'],
+          topic: ch.topic,
+          position: ch.position ?? 0,
+          createdAt: ch.createdAt,
+          lastMessageId: lastMsgMap.get(ch.id) ?? null,
+        })),
         members,
         roles: roles.map(r => ({
           id: r.id,
@@ -602,47 +632,70 @@ function buildReadyPayload(userId: string): {
     .where(eq(schema.dmMembers.userId, userId))
     .all();
 
+  const dmChannelIds = dmMemberships.map(dm => dm.dmChannelId);
   const dmChannels: DmChannel[] = [];
 
-  for (const dm of dmMemberships) {
-    const dmChannel = db.select()
-      .from(schema.dmChannels)
-      .where(eq(schema.dmChannels.id, dm.dmChannelId))
-      .get();
+  if (dmChannelIds.length > 0) {
+    // Batch: all DM channels (1 query)
+    const allDmChannelRows = batchInArray(
+      dmChannelIds,
+      ids => db.select().from(schema.dmChannels).where(inArray(schema.dmChannels.id, ids)).all(),
+    );
+    const dmChannelMap = new Map(allDmChannelRows.map(c => [c.id, c]));
 
-    if (!dmChannel) continue;
+    // Batch: all DM members across all channels (1 query)
+    const allDmMemberRows = batchInArray(
+      dmChannelIds,
+      ids => db.select().from(schema.dmMembers).where(inArray(schema.dmMembers.dmChannelId, ids)).all(),
+    );
 
-    const dmMemberRows = db.select()
-      .from(schema.dmMembers)
-      .where(eq(schema.dmMembers.dmChannelId, dm.dmChannelId))
-      .all();
-
-    const dmMemberUserIds = dmMemberRows.map(m => m.userId);
-    const dmUsers = dmMemberUserIds.length > 0
-      ? db.select().from(schema.users).where(inArray(schema.users.id, dmMemberUserIds)).all()
+    // Batch: all unique users from DM members (1 query)
+    const allDmUserIds = [...new Set(allDmMemberRows.map(m => m.userId))];
+    const allDmUsers = allDmUserIds.length > 0
+      ? batchInArray(allDmUserIds, ids => db.select().from(schema.users).where(inArray(schema.users.id, ids)).all())
       : [];
+    const dmUserMap = new Map(allDmUsers.map(u => [u.id, u]));
 
-    // Get last message
-    const lastMessage = db.select()
-      .from(schema.dmMessages)
-      .where(eq(schema.dmMessages.dmChannelId, dm.dmChannelId))
-      .orderBy(schema.dmMessages.createdAt)
-      .all();
+    // Batch: last message per DM channel (1 query — fixes the full-table-scan bug)
+    const dmLastMsgIdRows = batchInArray(
+      dmChannelIds,
+      ids => db.select({
+        dmChannelId: schema.dmMessages.dmChannelId,
+        lastId: sql<string>`max(${schema.dmMessages.id})`,
+      }).from(schema.dmMessages).where(inArray(schema.dmMessages.dmChannelId, ids)).groupBy(schema.dmMessages.dmChannelId).all(),
+    );
+    const dmLastMsgIds = dmLastMsgIdRows.map(r => r.lastId).filter((id): id is string => id != null);
+    const dmLastMessages = dmLastMsgIds.length > 0
+      ? batchInArray(dmLastMsgIds, ids => db.select().from(schema.dmMessages).where(inArray(schema.dmMessages.id, ids)).all())
+      : [];
+    const dmLastMsgMap = new Map(dmLastMessages.map(m => [m.dmChannelId, m]));
 
-    const last = lastMessage.length > 0 ? lastMessage[lastMessage.length - 1] : null;
+    // Assemble DM channels with zero additional queries
+    for (const dm of dmMemberships) {
+      const dmChannel = dmChannelMap.get(dm.dmChannelId);
+      if (!dmChannel) continue;
 
-    dmChannels.push({
-      id: dmChannel.id,
-      createdAt: dmChannel.createdAt,
-      members: dmUsers.map(sanitizeUser),
-      lastMessage: last ? {
-        id: last.id,
-        dmChannelId: last.dmChannelId,
-        userId: last.userId,
-        content: last.content,
-        createdAt: last.createdAt,
-      } : null,
-    });
+      const memberRows = allDmMemberRows.filter(m => m.dmChannelId === dm.dmChannelId);
+      const members = memberRows
+        .map(m => dmUserMap.get(m.userId))
+        .filter((u): u is NonNullable<typeof u> => u != null)
+        .map(sanitizeUser);
+
+      const last = dmLastMsgMap.get(dm.dmChannelId) ?? null;
+
+      dmChannels.push({
+        id: dmChannel.id,
+        createdAt: dmChannel.createdAt,
+        members,
+        lastMessage: last ? {
+          id: last.id,
+          dmChannelId: last.dmChannelId,
+          userId: last.userId,
+          content: last.content,
+          createdAt: last.createdAt,
+        } : null,
+      });
+    }
   }
 
   // Get Server Folders

packages/web/src/hooks/useLiveKit.ts

@@ -25,6 +25,7 @@ import {
   stopScreenShare,
   handleScreenShareUnpublished,
 } from '../utils/screenShare';
+import { getMediaStreamTrack } from '../utils/livekitInternals';
 
 let _activeRoom: Room | null = null;
 
@@ -522,7 +523,7 @@ export function useLiveKit() {
         const opts = buildScreenShareOptions(screenShareConfig);
         const screenPub = room.localParticipant.getTrackPublications().find(p => p.source === Track.Source.ScreenShare);
         if (screenPub?.videoTrack) {
-          const mediaTrack = (screenPub.videoTrack as any).mediaStreamTrack as MediaStreamTrack;
+          const mediaTrack = getMediaStreamTrack(screenPub.videoTrack);
           if (mediaTrack) {
             await mediaTrack.applyConstraints({ width: { ideal: opts.capture.width }, height: { ideal: opts.capture.height }, frameRate: { ideal: opts.capture.frameRate } });
             mediaTrack.contentHint = opts.contentHint;

packages/web/src/hooks/useTrackStats.ts

@@ -1,6 +1,7 @@
 import { useState, useEffect, useRef } from 'react';
 import { Track } from 'livekit-client';
 import { getActiveRoom } from './useLiveKit';
+import { discoverPeerConnections } from '../utils/livekitInternals';
 
 // ── Types ──
 
@@ -96,40 +97,6 @@ function reportKind(report: any): 'audio' | 'video' | null {
   return null;
 }
 
-/**
- * Discover all unique RTCPeerConnections from the LiveKit Room engine.
- * Different livekit-client versions expose the PC at different internal paths.
- */
-function discoverPeerConnections(room: any): RTCPeerConnection[] {
-  const engine = room?.engine;
-  if (!engine) return [];
-
-  const pcs: RTCPeerConnection[] = [];
-  const seen = new WeakSet<object>();
-
-  const tryAdd = (val: any) => {
-    if (val && typeof val.getStats === 'function' && !seen.has(val)) {
-      seen.add(val);
-      pcs.push(val);
-    }
-  };
-
-  // Current livekit-client (1.x+): engine.pcManager.{publisher,subscriber}.pc
-  tryAdd(engine.pcManager?.publisher?.pc);
-  tryAdd(engine.pcManager?.subscriber?.pc);
-  // Private backing field fallback
-  tryAdd(engine.pcManager?.publisher?._pc);
-  tryAdd(engine.pcManager?.subscriber?._pc);
-  // Older livekit-client paths
-  tryAdd(engine.publisher?.pc);
-  tryAdd(engine.subscriber?.pc);
-  // Unified-plan single PC
-  tryAdd(engine.pc);
-  tryAdd(room.pc);
-
-  return pcs;
-}
-
 function inferSimulcastLayer(width: number | null, height: number | null): string | null {
   if (height !== null && height > 0) {
     if (height >= 1000) return 'High';

packages/web/src/hooks/useWebSocket.ts

@@ -357,7 +357,7 @@ function connect(): void {
       if (ws.readyState === WebSocket.OPEN) {
         ws.send(JSON.stringify({ type: 'ping' }));
       }
-    }, 30_000);
+    }, 15_000);
   };
 
   ws.onmessage = (e) => {

packages/web/src/stores/authStore.ts

@@ -1,6 +1,10 @@
 import { create } from 'zustand';
 import type { User } from '@opencord/shared';
 import { api } from '../api/client';
+import { useChatStore } from './chatStore';
+import { useServerStore } from './serverStore';
+import { useSocialStore } from './socialStore';
+import { useVoiceStore } from './voiceStore';
 
 interface AuthState {
   token: string | null;
@@ -48,6 +52,11 @@ export const useAuthStore = create<AuthState>((set, get) => ({
 
   logout: () => {
     localStorage.removeItem('opencord_token');
+    // Clear all user-scoped state to prevent data leaking between sessions
+    useChatStore.getState().clearAllMessages();
+    useServerStore.getState().populateFromReady([], [], []);
+    useSocialStore.getState().reset();
+    useVoiceStore.getState().clearAllVoiceUsers();
     set({ token: null, user: null });
   },
 

packages/web/src/stores/chatStore.ts

@@ -5,6 +5,10 @@ import { wsSend } from '../hooks/useWebSocket';
 import { isDmChannel, useServerStore } from './serverStore';
 import { useAuthStore } from './authStore';
 
+const MAX_MESSAGES_PER_CHANNEL = 200;
+const MAX_CACHED_CHANNELS = 20;
+const EVICT_TO_CHANNELS = 15;
+
 interface TypingUser {
   userId: string;
   username: string;
@@ -27,6 +31,7 @@ interface ChatState {
   readStates: Map<string, string>;
   unreadChannels: Set<string>;
   realtimeMessageEvents: RealtimeMessageEvent[];
+  channelAccessTimes: Map<string, number>;
   setCurrentChannel: (channelId: string | null) => void;
   setReplyTo: (message: MessageWithUser | null) => void;
   loadMessages: (channelId: string, force?: boolean) => Promise<void>;
@@ -64,14 +69,59 @@ export const useChatStore = create<ChatState>((set, get) => ({
   readStates: new Map(),
   unreadChannels: new Set(),
   realtimeMessageEvents: [],
+  channelAccessTimes: new Map(),
 
-  setCurrentChannel: (channelId) => set({ currentChannelId: channelId }),
+  setCurrentChannel: (channelId) => {
+    set((state) => {
+      const newAccessTimes = new Map(state.channelAccessTimes);
+      if (channelId) {
+        newAccessTimes.set(channelId, Date.now());
+      }
+
+      // Evict stale channels if we have too many cached
+      let newMessages = state.messages;
+      let newHasMore = state.hasMore;
+      if (state.messages.size > MAX_CACHED_CHANNELS) {
+        const entries = [...newAccessTimes.entries()]
+          .filter(([id]) => id !== channelId)
+          .sort((a, b) => a[1] - b[1]);
+        const toEvict = state.messages.size - EVICT_TO_CHANNELS;
+        const evictIds = new Set(entries.slice(0, toEvict).map(([id]) => id));
+        if (evictIds.size > 0) {
+          newMessages = new Map(state.messages);
+          newHasMore = new Map(state.hasMore);
+          for (const id of evictIds) {
+            newMessages.delete(id);
+            newHasMore.delete(id);
+            newAccessTimes.delete(id);
+          }
+        }
+      }
+
+      return {
+        currentChannelId: channelId,
+        channelAccessTimes: newAccessTimes,
+        messages: newMessages,
+        hasMore: newHasMore,
+      };
+    });
+  },
   setReplyTo: (message) => set({ replyTo: message }),
 
-  clearAllMessages: () => set({ messages: new Map(), hasMore: new Map() }),
+  clearAllMessages: () => set({
+    messages: new Map(),
+    hasMore: new Map(),
+    typingUsers: new Map(),
+    readStates: new Map(),
+    unreadChannels: new Set(),
+    realtimeMessageEvents: [],
+    channelAccessTimes: new Map(),
+    currentChannelId: null,
+    replyTo: null,
+  }),
 
   loadMessages: async (channelId: string, force?: boolean) => {
-    if (!force && get().messages.has(channelId)) return;
+    if (!force && get().hasMore.has(channelId)) return;
     set({ isLoading: true, loadError: null });
     try {
       const isDm = isDmChannel(channelId);
@@ -84,7 +134,9 @@ export const useChatStore = create<ChatState>((set, get) => ({
         newMessages.set(channelId, messages as MessageWithUser[]);
         const newHasMore = new Map(state.hasMore);
         newHasMore.set(channelId, messages.length >= 50);
-        return { messages: newMessages, hasMore: newHasMore, isLoading: false, loadError: null };
+        const newAccessTimes = new Map(state.channelAccessTimes);
+        newAccessTimes.set(channelId, Date.now());
+        return { messages: newMessages, hasMore: newHasMore, channelAccessTimes: newAccessTimes, isLoading: false, loadError: null };
       });
     } catch (err) {
       set({ isLoading: false, loadError: (err as Error).message || 'Failed to load messages' });
@@ -232,7 +284,12 @@ export const useChatStore = create<ChatState>((set, get) => ({
         if (!m.id.startsWith('temp_') || m.userId !== message.userId) return true;
         return m.content !== message.content;
       });
-      newMessages.set(channelId, [...filtered, message]);
+      let updated = [...filtered, message];
+      // Cap per-channel messages to prevent memory growth
+      if (updated.length > MAX_MESSAGES_PER_CHANNEL) {
+        updated = updated.slice(updated.length - MAX_MESSAGES_PER_CHANNEL);
+      }
+      newMessages.set(channelId, updated);
       return { messages: newMessages };
     });
   },
@@ -248,7 +305,12 @@ export const useChatStore = create<ChatState>((set, get) => ({
         if (!m.id.startsWith('temp_') || m.userId !== message.userId) return true;
         return m.content !== message.content;
       });
-      newMessages.set(channelId, [...filtered, message]);
+      let updated = [...filtered, message];
+      // Cap per-channel messages to prevent memory growth
+      if (updated.length > MAX_MESSAGES_PER_CHANNEL) {
+        updated = updated.slice(updated.length - MAX_MESSAGES_PER_CHANNEL);
+      }
+      newMessages.set(channelId, updated);
       // Append to realtimeMessageEvents (capped at 50)
       const newEvents = [...state.realtimeMessageEvents, { channelId, message }];
       if (newEvents.length > 50) newEvents.splice(0, newEvents.length - 50);

packages/web/src/stores/socialStore.ts

@@ -18,6 +18,7 @@ interface SocialState {
   addFriendFromAccepted: (friend: Friend, requestId: string) => void;
   updateFriendPresence: (userId: string, status: string) => void;
   removeFriendLocally: (userId: string) => void;
+  reset: () => void;
 }
 
 export const useSocialStore = create<SocialState>((set, get) => ({
@@ -139,4 +140,6 @@ export const useSocialStore = create<SocialState>((set, get) => ({
       ),
     }));
   },
+
+  reset: () => set({ friends: [], requests: [], isLoading: false, error: null }),
 }));

packages/web/src/utils/livekitInternals.ts

@@ -0,0 +1,62 @@
+import type { Room } from 'livekit-client';
+
+/**
+ * Discover all unique RTCPeerConnections from the LiveKit Room engine.
+ * Different livekit-client versions expose the PC at different internal paths.
+ */
+export function discoverPeerConnections(room: Room): RTCPeerConnection[] {
+  const engine = (room as any)?.engine;
+  if (!engine) return [];
+
+  const pcs: RTCPeerConnection[] = [];
+  const seen = new WeakSet<object>();
+
+  const tryAdd = (val: any) => {
+    if (val && typeof val.getStats === 'function' && !seen.has(val)) {
+      seen.add(val);
+      pcs.push(val);
+    }
+  };
+
+  // Current livekit-client (1.x+): engine.pcManager.{publisher,subscriber}.pc
+  tryAdd(engine.pcManager?.publisher?.pc);
+  tryAdd(engine.pcManager?.subscriber?.pc);
+  // Private backing field fallback
+  tryAdd(engine.pcManager?.publisher?._pc);
+  tryAdd(engine.pcManager?.subscriber?._pc);
+  // Older livekit-client paths
+  tryAdd(engine.publisher?.pc);
+  tryAdd(engine.subscriber?.pc);
+  // Unified-plan single PC
+  tryAdd(engine.pc);
+  tryAdd((room as any).pc);
+
+  return pcs;
+}
+
+/**
+ * Get the publisher RTCPeerConnection from a LiveKit Room.
+ * Used by overdrive to inject RTP sender parameters.
+ */
+export function getPublisherPC(room: Room): RTCPeerConnection | null {
+  const engine = (room as any)?.engine;
+  if (!engine) return null;
+
+  return (
+    engine.pcManager?.publisher?.pc ??
+    engine.pcManager?.publisher?._pc ??
+    engine.publisher?.pc ??
+    engine.pc ??
+    null
+  );
+}
+
+/**
+ * Safely extract the underlying MediaStreamTrack from a LiveKit track object.
+ * Handles both public `.mediaStreamTrack` and private `._mediaStreamTrack`.
+ */
+export function getMediaStreamTrack(track: unknown): MediaStreamTrack | null {
+  if (!track) return null;
+  const t = track as any;
+  return t.mediaStreamTrack ?? t._mediaStreamTrack ?? null;
+}

packages/web/src/utils/screenShare.ts

@@ -3,6 +3,7 @@ import { useVoiceStore } from '../stores/voiceStore';
 import type { ScreenShareConfig } from '../stores/voiceStore';
 import { AudioManager } from '../audio/AudioManager';
 import { wsSend } from '../hooks/useWebSocket';
+import { getPublisherPC, getMediaStreamTrack } from './livekitInternals';
 
 // ---------------------------------------------------------------------------
 // Types
@@ -87,12 +88,12 @@ export async function applyOverdrive(
     const pub = room.localParticipant.getTrackPublications().find(p => p.source === source);
     if (!pub?.track) return;
 
-    const engine = (room as any).engine;
-    const pc = engine?.pcManager?.publisher?.pc || engine?.publisher?.pc || engine?.pc;
+    const pc = getPublisherPC(room);
     if (!pc) return;
 
-    const senders = (pc as RTCPeerConnection).getSenders();
-    const sender = senders.find(s => s.track?.id === (pub.track as any).mediaStreamTrack?.id);
+    const pubMediaTrack = getMediaStreamTrack(pub.track);
+    const senders = pc.getSenders();
+    const sender = senders.find(s => s.track?.id === pubMediaTrack?.id);
     if (!sender) return;
 
     const params = sender.getParameters();