refactor(scribe): remove calendar + entity surfaces from web UI (frontend)

Frontend half of the narrowing (milestone #194); matches backend b49efdc.

- delete CalendarView, EventSlideOver, WeatherCard (orphan)
- drop /calendar route + nav link + the g→l keyboard shortcut
- strip the calendar-events API client + event/metadata bits from note
  types and the notes store
- KnowledgeView: remove People/Places/Lists tabs, entity cards, create
  buttons and the upcoming-events widget; keep notes/tasks/plans/processes
  + the overdue-task badge
- NoteEditorView: remove person/place/list forms + list-builder + entity
  metadata; keep note + process editors (type select = Note/Process)
- DashboardView: drop the "Upcoming · 7 days" events rail card
- SettingsView: remove the CalDAV integration card + save/test (its
  endpoints were deleted backend-side)
- prune the now-dead entity/event CSS

RecurrenceEditor + task recurrence rules are kept (task machinery, not
calendar). Verified by a full dangler sweep.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BPtbSzA4JLMAKgFZ8VTg7Q

frontend/src/components/AppHeader.vue

@@ -47,7 +47,6 @@ router.afterEach(() => {
         <div class="nav-pill-bar">
           <router-link to="/dashboard" class="nav-link">Dashboard</router-link>
           <router-link to="/knowledge" class="nav-link" :class="{ 'router-link-active': isKnowledgeActive }">Browse</router-link>
-          <router-link to="/calendar" class="nav-link">Calendar</router-link>
           <router-link to="/projects" class="nav-link">Projects</router-link>
           <router-link to="/rules" class="nav-link">Rulebooks</router-link>
         </div>
@@ -93,7 +92,6 @@ router.afterEach(() => {
     <div v-if="mobileMenuOpen" class="mobile-menu">
       <router-link to="/dashboard" class="nav-link">Dashboard</router-link>
       <router-link to="/knowledge" class="nav-link" :class="{ 'router-link-active': isKnowledgeActive }">Browse</router-link>
-      <router-link to="/calendar" class="nav-link">Calendar</router-link>
       <router-link to="/projects" class="nav-link">Projects</router-link>
       <router-link to="/rules" class="nav-link">Rulebooks</router-link>
       <router-link to="/shared" class="nav-link">Shared</router-link>