Refactor: naming, type safety, consistency across panel system

- AppToolbar: rename togglePanel→toggleDropdown to avoid collision with
  debug panel toggle from usePanels
- ChatPane: computed()→toRef() for props passed to composables (consistent)
- ChatPane: add console.warn on session history fetch failure
- DebugColumn: skip object spread when no new panels resolved (perf)
- AgentsView: remove unused wsSwitchAgent, annotate disabled picker

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/AppToolbar.vue

@@ -1,7 +1,7 @@
 <template>
     <div v-if="isLoggedIn" class="app-toolbar">
         <!-- Connection pill -->
-        <button class="toolbar-pill" :class="{ active: connActive }" @click="togglePanel('conn')" :title="connLabel || 'Connection'">
+        <button class="toolbar-pill" :class="{ active: connActive }" @click="toggleDropdown('conn')" :title="connLabel || 'Connection'">
             <WifiIcon class="w-4 h-4" />
             <span v-if="connLabel" class="toolbar-pill-label">{{ connLabel }}</span>
         </button>
@@ -57,7 +57,7 @@
             v-if="takeoverToken"
             class="toolbar-pill"
             :class="{ active: captureActive }"
-            @click="togglePanel('takeover')"
+            @click="toggleDropdown('takeover')"
             title="Takeover"
         >
             <SignalIcon class="w-4 h-4" />
@@ -69,10 +69,10 @@
         </button>
 
         <!-- Panels (dropdown from toolbar) -->
-        <div v-if="openPanel" class="toolbar-panel-backdrop" @click="openPanel = null" />
+        <div v-if="openDropdown" class="toolbar-panel-backdrop" @click="openDropdown = null" />
 
         <!-- Connection panel -->
-        <div v-if="openPanel === 'conn'" class="toolbar-panel" style="right: auto; left: 0;">
+        <div v-if="openDropdown === 'conn'" class="toolbar-panel" style="right: auto; left: 0;">
             <div class="toolbar-panel-header">Connection</div>
             <div class="toolbar-panel-row"><span>HTTP</span><span>{{ chatStore.connectionState }}</span></div>
             <div class="toolbar-panel-row"><span>Channel</span><span>{{ chatStore.channelState }}</span></div>
@@ -81,7 +81,7 @@
         </div>
 
         <!-- Takeover panel -->
-        <div v-if="openPanel === 'takeover'" class="toolbar-panel" style="right: 0;">
+        <div v-if="openDropdown === 'takeover'" class="toolbar-panel" style="right: 0;">
             <div class="toolbar-panel-header">Takeover</div>
             <div class="toolbar-panel-token" @click="copyToken" :title="tokenCopied ? 'Copied!' : 'Click to copy'">
                 <code>{{ takeoverToken }}</code>
@@ -164,7 +164,7 @@ function copyToken() {
 
 function revokeAndClose() {
     takeover.revoke();
-    openPanel.value = null;
+    openDropdown.value = null;
 }
 
 // Version
@@ -181,11 +181,11 @@ function copyVersionDetails() {
     setTimeout(() => { versionCopied.value = false; }, 2000);
 }
 
-// Panel toggle
-const openPanel = ref<'conn' | 'takeover' | null>(null);
+// Toolbar dropdown (conn/takeover panels — distinct from debug panel toggles)
+const openDropdown = ref<'conn' | 'takeover' | null>(null);
 
-function togglePanel(panel: 'conn' | 'takeover') {
-    openPanel.value = openPanel.value === panel ? null : panel;
+function toggleDropdown(panel: 'conn' | 'takeover') {
+    openDropdown.value = openDropdown.value === panel ? null : panel;
 }
 </script>
 

src/components/ChatPane.vue

@@ -259,7 +259,7 @@ async function fetchPreviousSession(loadMore = false) {
         }
         prevSkip.value = skip + newSessions.length;
         prevHasMore.value = data.hasMore ?? false;
-    } catch { /* silently fail */ }
+    } catch (err) { console.warn('[chat] session history fetch failed:', err); }
     finally { prevLoading.value = false; }
 }
 
@@ -288,8 +288,8 @@ const visibleCount = ref(VISIBLE_PAGE);
 const { groupedVisibleMsgs, hasMore, loadMore, getFormattedAgentName } = useMessageGrouping(
     computed(() => chatStore.messages),
     visibleCount,
-    computed(() => props.selectedAgent),
-    computed(() => props.allAgents),
+    toRef(props, 'selectedAgent'),
+    toRef(props, 'allAgents'),
     toRef(chatStore, 'sessionKey'),
 );
 
@@ -421,7 +421,7 @@ function onConfirmNew() {
 }
 
 const { inputEl, isShaking, autoGrow, triggerShake } = useInputAutogrow(input);
-const { isAgentRunning } = useAgentDisplay(computed(() => props.selectedAgent), computed(() => props.defaultAgent), computed(() => props.allAgents));
+const { isAgentRunning } = useAgentDisplay(toRef(props, 'selectedAgent'), toRef(props, 'defaultAgent'), toRef(props, 'allAgents'));
 
 // Attachments
 const { attachments, addFiles, removeAttachment, clearAttachments, toPayload, hasAttachments } = useAttachments();

src/components/DebugColumn.vue

@@ -39,13 +39,16 @@ const { openSidePanels, closePanel } = usePanels();
 const resolvedComponents = shallowRef<Record<string, Component>>({});
 
 watch(openSidePanels, (panels) => {
-    const current = { ...resolvedComponents.value };
+    const current = resolvedComponents.value;
+    let changed = false;
+    const updates = { ...current };
     for (const panel of panels) {
-        if (!current[panel.id]) {
-            current[panel.id] = defineAsyncComponent(panel.component);
+        if (!updates[panel.id]) {
+            updates[panel.id] = defineAsyncComponent(panel.component);
+            changed = true;
         }
     }
-    resolvedComponents.value = current;
+    if (changed) resolvedComponents.value = updates;
 }, { immediate: true });
 
 function panelProps(id: PanelId): Record<string, any> {

src/views/AgentsView.vue

@@ -83,11 +83,12 @@ const agentsRoute = useRoute();
 const { isChatOpen, isWorkspaceOpen, hasDebugColumn } = usePanels();
 
 // Auth + agents
-const { connected, send: wsSend, switchAgent: wsSwitchAgent } = ws;
+const { connected, send: wsSend } = ws;
 const { isLoggedIn } = auth;
 const { selectedAgent, selectedMode, filteredAgents, defaultAgent, allAgents } = agents;
 
-// Agent picker
+// Agent picker — disabled for now (auto-select default agent)
+// TODO: re-enable when multi-agent UX is designed
 const showPicker = computed(() => false);
 const SEGMENTS = ['personal', 'common', 'private', 'public'] as const;
 const agentSegments = computed(() =>