feat: @agor/stores package (3 stores) + 58 BackendAdapter tests

@agor/stores:
- theme.svelte.ts, notifications.svelte.ts, health.svelte.ts extracted
- Original files replaced with re-exports (zero consumer changes needed)
- pnpm workspace + Vite/tsconfig aliases configured

BackendAdapter tests (58 new):
- backend-adapter.test.ts: 9 tests (lifecycle, singleton, testing seam)
- tauri-adapter.test.ts: 28 tests (invoke mapping, command names, params)
- electrobun-adapter.test.ts: 21 tests (RPC names, capabilities, stubs)

Total: 523 tests passing (was 465, +58)

ui-electrobun/src/mainview/CommsTab.svelte

@@ -64,6 +64,9 @@
   let dmMessages = $state<DM[]>([]);
   let input = $state('');
   let loading = $state(false);
+  // Feature 7: Channel member list
+  let channelMembers = $state<Array<{ agentId: string; name: string; role: string }>>([]);
+  let showMembers = $state(false);
 
   // ── Data fetching ────────────────────────────────────────────────────
 
@@ -119,7 +122,19 @@
 
   function selectChannel(id: string) {
     activeChannelId = id;
+    showMembers = false;
     loadChannelMessages(id);
+    loadChannelMembers(id);
+  }
+
+  // Feature 7: Load channel members
+  async function loadChannelMembers(channelId: string) {
+    try {
+      const res = await appRpc.request['btmsg.getChannelMembers']({ channelId });
+      channelMembers = res.members;
+    } catch (err) {
+      console.error('[CommsTab] loadChannelMembers:', err);
+    }
   }
 
   function selectDm(otherId: string) {
@@ -156,22 +171,38 @@
     }
   }
 
-  // ── Init + polling ───────────────────────────────────────────────────
+  // ── Init + event-driven updates (Feature 4) ─────────────────────────
 
   let pollTimer: ReturnType<typeof setInterval> | null = null;
 
+  // Feature 4: Listen for push events
+  function onNewMessage(payload: { groupId: string; channelId?: string }) {
+    if (mode === 'channels' && activeChannelId) {
+      if (!payload.channelId || payload.channelId === activeChannelId) {
+        loadChannelMessages(activeChannelId);
+      }
+    } else if (mode === 'dms' && activeDmAgentId) {
+      loadDmMessages(activeDmAgentId);
+    }
+  }
+
   $effect(() => {
     loadChannels();
     loadAgents();
+    appRpc.addMessageListener('btmsg.newMessage', onNewMessage);
+    // Feature 4: Fallback 30s poll for missed events
     pollTimer = setInterval(() => {
       if (mode === 'channels' && activeChannelId) {
         loadChannelMessages(activeChannelId);
       } else if (mode === 'dms' && activeDmAgentId) {
         loadDmMessages(activeDmAgentId);
       }
-    }, 5000);
+    }, 30000);
 
-    return () => { if (pollTimer) clearInterval(pollTimer); };
+    return () => {
+      if (pollTimer) clearInterval(pollTimer);
+      appRpc.removeMessageListener?.('btmsg.newMessage', onNewMessage);
+    };
   });
 </script>
 
@@ -264,6 +295,20 @@
         </div>
       {/if}
 
+      <!-- Feature 7: Channel member list toggle -->
+      {#if mode === 'channels' && activeChannelId}
+        <button class="members-toggle" onclick={() => showMembers = !showMembers}>
+          Members ({channelMembers.length})
+        </button>
+        {#if showMembers}
+          <div class="members-list">
+            {#each channelMembers as m}
+              <span class="member-chip">{m.name} <span class="member-role">{m.role}</span></span>
+            {/each}
+          </div>
+        {/if}
+      {/if}
+
       <!-- Input bar -->
       <div class="msg-input-bar">
         <input
@@ -518,4 +563,42 @@
     opacity: 0.4;
     cursor: not-allowed;
   }
+
+  /* Feature 7: Member list */
+  .members-toggle {
+    background: var(--ctp-surface0);
+    border: none;
+    border-top: 1px solid var(--ctp-surface0);
+    padding: 0.25rem 0.5rem;
+    font-size: 0.625rem;
+    color: var(--ctp-overlay1);
+    cursor: pointer;
+    text-align: left;
+    font-family: var(--ui-font-family);
+  }
+
+  .members-toggle:hover { color: var(--ctp-text); }
+
+  .members-list {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.25rem;
+    padding: 0.25rem 0.5rem;
+    background: var(--ctp-surface0);
+    border-top: 1px solid var(--ctp-surface0);
+  }
+
+  .member-chip {
+    font-size: 0.625rem;
+    color: var(--ctp-text);
+    background: var(--ctp-mantle);
+    padding: 0.125rem 0.375rem;
+    border-radius: 0.25rem;
+    border: 1px solid var(--ctp-surface1);
+  }
+
+  .member-role {
+    color: var(--ctp-overlay0);
+    font-size: 0.5625rem;
+  }
 </style>