fix: repair invite links, social features, messaging + Discord UI overhaul

Phase 1 - Feature Repair:
- Fix member kick/leave: add missing db.delete() call in servers.ts
- Stabilize invite codes: return existing code instead of regenerating
- Fix user search: use LIKE instead of exact match in social.ts
- Wire DM button on FriendsPage to create/navigate to DM channels
- Add cancel outgoing friend request (DELETE endpoint + frontend)
- Add accept/decline friend request actions with WS real-time events
- Fix replyToId persistence in message creation
- Hydrate reactions and replyTo in message queries
- Add joinByCode to API client and serverStore
- Add friend_request_received/accepted WebSocket events

Phase 2 - Discord UI Overhaul:
- Remove stray borders between layout columns
- Replace shadow-sm with shadow-header on content headers
- Replace all bg-gray-*/text-gray-* with Discord color tokens
- Ensure flat color contrast (#1E1F22, #2B2D31, #313338)

Testing:
- Set up vitest + @testing-library/react + jsdom
- Add 17 tests across InviteModal, JoinServer, FriendsPage (all passing)
- Fix vite resolve.extensions to prefer .tsx over stale .js files

packages/server/src/db/migrate.ts

@@ -0,0 +1,45 @@
+import Database from 'better-sqlite3';
+
+export function runMigrations(db: Database.Database): void {
+  console.log('Checking for database migrations...');
+
+  const tables = [
+    {
+      name: 'messages',
+      columns: [
+        { name: 'reply_to_id', type: 'TEXT REFERENCES messages(id) ON DELETE SET NULL' }
+      ]
+    },
+    {
+      name: 'users',
+      columns: [
+        { name: 'status', type: "TEXT DEFAULT 'offline'" },
+        { name: 'custom_status', type: 'TEXT' }
+      ]
+    },
+    {
+      name: 'roles',
+      columns: [
+        { name: 'permissions', type: 'TEXT' }
+      ]
+    }
+  ];
+
+  for (const table of tables) {
+    const tableInfo = db.pragma(`table_info(${table.name})`) as { name: string }[];
+    const existingColumns = new Set(tableInfo.map(c => c.name));
+
+    for (const column of table.columns) {
+      if (!existingColumns.has(column.name)) {
+        console.log(`Migrating: Adding column ${column.name} to ${table.name}`);
+        try {
+          db.exec(`ALTER TABLE ${table.name} ADD COLUMN ${column.name} ${column.type}`);
+        } catch (error) {
+          console.error(`Failed to add column ${column.name} to ${table.name}:`, error);
+        }
+      }
+    }
+  }
+  
+  console.log('Migrations complete.');
+}