refactor(ui): Phase 7 — strip chat/voice/journal/workspace/home surfaces

Frontend deletion phase of the MCP-first pivot. All in-app
conversational surfaces are gone — Claude/MCP is the assistant now.

Deleted views:
  ChatView, JournalView, WorkspaceView, HomeView

Deleted components:
  ChatPanel, ChatInputBar, ChatMessage, ChatStreamingBubble,
  ToolCallCard, ToolConfirmCard, WorkspaceChatWidget

Deleted composables + store:
  useVoiceRecorder, useVoiceAudio, useStreamingTts, stores/chat

Router changes:
  - / now redirects to /knowledge (was /journal)
  - dropped /chat, /chat/:id, /journal, /workspace/:projectId
  - /tasks still redirects to / (→ /knowledge)
  - /notes still redirects to /knowledge

KnowledgeView:
  - removed ChatPanel + ChatInputBar embeds
  - removed minichat floating widget + state + handlers
  - removed Chat link from today bar
  - removed `chatStore` driven auto-refresh-on-tool-call watch

App.vue:
  - removed useChatStore + startStatusPolling/stopStatusPolling
  - removed VAD ONNX preloader (voice subsystem dead)
  - removed visibilitychange listener (only did voice status re-check)
  - removed `c` single-key shortcut (focus chat / goto chat)
  - removed `g+c` two-key sequence (goto chat)
  - removed Chat section from shortcuts overlay
  - removed `.chat-page` / `.workspace-root` CSS overflow rule

AppHeader.vue:
  - removed useChatStore + status indicator (Ollama model status)
  - removed Chat / Journal nav links (desktop + mobile)

SettingsView.vue (4598 → 4079 lines):
  - removed Voice tab entirely
  - Notifications tab: dropped Push Notifications + Chat History
    + About sections (kept Email Notifications)
  - General tab: dropped Assistant (name + model pickers) +
    Model Management sections (kept Tasks + Timezone)
  - Profile tab: dropped Journal + Observations sections
  - VALID_TABS + tab list array no longer include "voice"
  - removed `loadVoiceTab()` activation trigger

Service worker (frontend/public/sw.js):
  - dropped push and notificationclick handlers (push subsystem
    only fired on internal generation completion, which is gone)
  - kept empty fetch handler as PWA installability shell

Script-level dead code (state refs, helper functions referencing
removed APIs) remains in SettingsView and stores/push.ts and
stores/settings.ts for now — Phase 8 backend deletion will clean
those up alongside the matching backend route removals.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/router/index.ts

@@ -5,11 +5,10 @@ const router = createRouter({
   history: createWebHistory(),
   routes: [
     {
-      // Root lands on the journal. To revert to Knowledge as home, change
-      // the redirect target below to "/knowledge" (Knowledge stays a real
-      // route at /knowledge, so the swap is a one-line edit).
+      // Knowledge is the landing page in the MCP-first architecture
+      // (chat / journal / workspace surfaces have been removed).
       path: "/",
-      redirect: "/journal",
+      redirect: "/knowledge",
     },
     {
       path: "/knowledge",
@@ -80,11 +79,6 @@ const router = createRouter({
       name: "project-view",
       component: () => import("@/views/ProjectView.vue"),
     },
-    {
-      path: "/workspace/:projectId",
-      name: "workspace",
-      component: () => import("@/views/WorkspaceView.vue"),
-    },
     {
       path: "/tasks",
       redirect: "/",
@@ -99,16 +93,6 @@ const router = createRouter({
       name: "task-edit",
       component: () => import("@/views/TaskEditorView.vue"),
     },
-    {
-      path: "/chat",
-      name: "chat",
-      component: () => import("@/views/ChatView.vue"),
-    },
-    {
-      path: "/chat/:id",
-      name: "chat-conversation",
-      component: () => import("@/views/ChatView.vue"),
-    },
     {
       path: "/shared",
       name: "shared-with-me",
@@ -119,11 +103,6 @@ const router = createRouter({
       name: "calendar",
       component: () => import("@/views/CalendarView.vue"),
     },
-    {
-      path: "/journal",
-      name: "journal",
-      component: () => import("@/views/JournalView.vue"),
-    },
     {
       path: "/settings",
       name: "settings",