feat: restore last active channel on login

- Channel store saves {serverId, channelId} to localStorage on select
- ServerBar restores last server+channel after fetching servers
- Fetches channels for the saved server, then sets the channel if valid
- Gracefully handles missing/deleted servers or channels

web/src/components/ServerBar.tsx

@@ -34,8 +34,28 @@ export function ServerBar() {
   const { showMenu, MenuPortal } = useContextMenu();
 
   useEffect(() => {
-    fetchServers();
-  }, [fetchServers]);
+    fetchServers().then(() => {
+      // ponytail: restore last active server + channel from localStorage
+      try {
+        const raw = localStorage.getItem('dumpster:lastChannel');
+        if (raw) {
+          const { serverId, channelId } = JSON.parse(raw);
+          const srv = useServerStore.getState().servers.find((s) => s.id === serverId);
+          if (srv) {
+            setActiveServer(serverId);
+            setDM(false);
+            // Fetch channels then restore the channel
+            useChannelStore.getState().fetchChannels(serverId).then(() => {
+              const ch = useChannelStore.getState().channelsByServer[serverId]?.find((c) => c.id === channelId);
+              if (ch) {
+                setActiveChannel(channelId);
+              }
+            });
+          }
+        }
+      } catch { /* ignore bad localStorage */ }
+    });
+  }, [fetchServers, setActiveServer, setActiveChannel, setDM]);
 
   const handleSelect = (id: string) => {
     setActiveServer(id);

web/src/stores/channel.ts

@@ -48,7 +48,19 @@ export const useChannelStore = create<ChannelState>((set) => ({
     }
   },
 
-  setActiveChannel: (id) => set({ activeChannelId: id }),
+  setActiveChannel: (id) => {
+    set({ activeChannelId: id });
+    if (id) {
+      // ponytail: persist last active channel for session restore
+      const state = useChannelStore.getState();
+      for (const [serverId, channels] of Object.entries(state.channelsByServer)) {
+        if (channels.some((c) => c.id === id)) {
+          localStorage.setItem('dumpster:lastChannel', JSON.stringify({ serverId, channelId: id }));
+          break;
+        }
+      }
+    }
+  },
 
   addChannel: (channel) =>
     set((state) => {