feat: unread indicators + DM bug fixes + data-driven isDmChannel

- Fix stale message cache: add force param to loadMessages, clearAllMessages action
- Fix reload race condition: URL-based isDmChannel fallback before WS ready
- Add read_states DB table for persistent unread tracking
- Add channel_ack WS event (client→server→echo) with BigInt comparison
- Wire up unread state in chatStore (readStates, unreadChannels, ackChannel)
- Auto-ack channels on MessageList view (200ms debounced)
- Unread pill indicators on server icons in ServerSidebar
- Bold text + white dot on unread channels/DMs in ChannelSidebar
- Replace all showDms reads with data-driven isDmChannel() across 8 files
- Design system, UI polish, and component fixes from previous sessions

packages/web/src/components/layout/ChannelSidebar.tsx

@@ -18,6 +18,7 @@ export function ChannelSidebar() {
   const dmChannels = useServerStore((s) => s.dmChannels);
   const currentChannelId = useChatStore((s) => s.currentChannelId);
   const setCurrentChannel = useChatStore((s) => s.setCurrentChannel);
+  const unreadChannels = useChatStore((s) => s.unreadChannels);
   const openModal = useUIStore((s) => s.openModal);
   const user = useAuthStore((s) => s.user);
   const members = useServerStore((s) => s.members);
@@ -113,20 +114,30 @@ export function ChannelSidebar() {
             {dmChannels.map((dm) => {
               const otherUser = dm.members.find(m => m.id !== user?.id);
               if (!otherUser) return null;
-              
+              const isDmUnread = unreadChannels.has(dm.id) && currentChannelId !== dm.id;
+
               return (
-                <div 
+                <div
                   key={dm.id}
                   onClick={() => handleChannelClick(dm.id)}
-                  className={`flex items-center gap-3 px-2 h-[42px] rounded-[4px] cursor-pointer transition-colors group ${
-                    currentChannelId === dm.id 
-                      ? 'bg-discord-modifier-selected text-white' 
-                      : 'text-discord-text-muted hover:bg-discord-modifier-hover hover:text-discord-text-secondary'
+                  className={`relative flex items-center gap-3 px-2 h-[42px] rounded-[4px] cursor-pointer transition-colors group ${
+                    currentChannelId === dm.id
+                      ? 'bg-discord-modifier-selected text-white'
+                      : isDmUnread
+                        ? 'text-white hover:bg-discord-modifier-hover'
+                        : 'text-discord-text-muted hover:bg-discord-modifier-hover hover:text-discord-text-secondary'
                   }`}
                 >
+                  {isDmUnread && (
+                    <div className="absolute -left-1 w-1 h-2 bg-white rounded-r-full" />
+                  )}
                   <Avatar src={otherUser.avatar} name={otherUser.displayName ?? otherUser.username} size={32} status={otherUser.status as any} />
                   <div className="flex-1 min-w-0">
-                    <div className={`text-[16px] font-medium truncate ${currentChannelId === dm.id ? 'text-white' : 'text-discord-text-muted group-hover:text-discord-text-secondary'}`}>
+                    <div className={`text-[16px] truncate ${
+                      currentChannelId === dm.id ? 'text-white font-medium'
+                        : isDmUnread ? 'text-white font-bold'
+                        : 'text-discord-text-muted group-hover:text-discord-text-secondary font-medium'
+                    }`}>
                       {otherUser.displayName ?? otherUser.username}
                     </div>
                   </div>
@@ -194,22 +205,30 @@ export function ChannelSidebar() {
             )}
           </div>
           <div className="space-y-[2px]">
-            {textChannels.map((channel) => (
-              <button
-                key={channel.id}
-                onClick={() => handleChannelClick(channel.id)}
-                className={`w-full flex items-center gap-1.5 px-2 h-8 rounded-[4px] group transition-colors ${
-                  currentChannelId === channel.id
-                    ? 'bg-discord-modifier-selected text-white'
-                    : 'text-discord-text-muted hover:text-discord-text-secondary hover:bg-discord-modifier-hover'
-                }`}
-              >
-                <svg width="20" height="20" viewBox="0 0 24 24" fill="currentColor" className="flex-shrink-0 opacity-60">
-                  <path d="M5.88657 21C5.57547 21 5.3399 20.7189 5.39427 20.4126L6.00001 17H2.59511C2.28449 17 2.04905 16.7198 2.10259 16.4138L2.27759 15.4138C2.31946 15.1746 2.52722 15 2.77011 15H6.35001L7.41001 9H4.00511C3.69449 9 3.45905 8.71977 3.51259 8.41381L3.68759 7.41381C3.72946 7.17456 3.93722 7 4.18011 7H7.76001L8.39677 3.41262C8.43914 3.17391 8.64664 3 8.88907 3H9.87344C10.1845 3 10.4201 3.28107 10.3657 3.58738L9.76001 7H15.76L16.3968 3.41262C16.4391 3.17391 16.6466 3 16.8891 3H17.8734C18.1845 3 18.4201 3.28107 18.3657 3.58738L17.76 7H21.1649C21.4755 7 21.711 7.28023 21.6574 7.58619L21.4824 8.58619C21.4406 8.82544 21.2328 9 20.9899 9H17.41L16.35 15H19.7549C20.0655 15 20.301 15.2802 20.2474 15.5862L20.0724 16.5862C20.0306 16.8254 19.8228 17 19.5799 17H16L15.3632 20.5874C15.3209 20.8261 15.1134 21 14.8709 21H13.8866C13.5755 21 13.3399 20.7189 13.3943 20.4126L14 17H8.00001L7.36325 20.5874C7.32088 20.8261 7.11337 21 6.87094 21H5.88657ZM9.41001 9L8.35001 15H14.35L15.41 9H9.41001Z" />
-                </svg>
-                <span className="truncate font-medium text-[16px]">{channel.name}</span>
-              </button>
-            ))}
+            {textChannels.map((channel) => {
+              const isUnread = unreadChannels.has(channel.id) && currentChannelId !== channel.id;
+              return (
+                <button
+                  key={channel.id}
+                  onClick={() => handleChannelClick(channel.id)}
+                  className={`w-full flex items-center gap-1.5 px-2 h-8 rounded-[4px] group transition-colors ${
+                    currentChannelId === channel.id
+                      ? 'bg-discord-modifier-selected text-white'
+                      : isUnread
+                        ? 'text-white hover:text-white hover:bg-discord-modifier-hover'
+                        : 'text-discord-text-muted hover:text-discord-text-secondary hover:bg-discord-modifier-hover'
+                  }`}
+                >
+                  {isUnread && (
+                    <div className="absolute -left-0.5 w-1 h-2 bg-white rounded-r-full" />
+                  )}
+                  <svg width="20" height="20" viewBox="0 0 24 24" fill="currentColor" className="flex-shrink-0 opacity-60">
+                    <path d="M5.88657 21C5.57547 21 5.3399 20.7189 5.39427 20.4126L6.00001 17H2.59511C2.28449 17 2.04905 16.7198 2.10259 16.4138L2.27759 15.4138C2.31946 15.1746 2.52722 15 2.77011 15H6.35001L7.41001 9H4.00511C3.69449 9 3.45905 8.71977 3.51259 8.41381L3.68759 7.41381C3.72946 7.17456 3.93722 7 4.18011 7H7.76001L8.39677 3.41262C8.43914 3.17391 8.64664 3 8.88907 3H9.87344C10.1845 3 10.4201 3.28107 10.3657 3.58738L9.76001 7H15.76L16.3968 3.41262C16.4391 3.17391 16.6466 3 16.8891 3H17.8734C18.1845 3 18.4201 3.28107 18.3657 3.58738L17.76 7H21.1649C21.4755 7 21.711 7.28023 21.6574 7.58619L21.4824 8.58619C21.4406 8.82544 21.2328 9 20.9899 9H17.41L16.35 15H19.7549C20.0655 15 20.301 15.2802 20.2474 15.5862L20.0724 16.5862C20.0306 16.8254 19.8228 17 19.5799 17H16L15.3632 20.5874C15.3209 20.8261 15.1134 21 14.8709 21H13.8866C13.5755 21 13.3399 20.7189 13.3943 20.4126L14 17H8.00001L7.36325 20.5874C7.32088 20.8261 7.11337 21 6.87094 21H5.88657ZM9.41001 9L8.35001 15H14.35L15.41 9H9.41001Z" />
+                  </svg>
+                  <span className={`truncate text-[16px] ${isUnread ? 'font-bold' : 'font-medium'}`}>{channel.name}</span>
+                </button>
+              );
+            })}
           </div>
         </div>