Mitra Bestie §1–§3: shell + Undangan + popup + chat polish

Brings the mitra app to figma-bestie parity for Home (§1), Undangan
inbox with Curhat Baru + Perpanjang tabs (§2), and the incoming-popup
+ active-chat flow (§3). Home now lives inside a StatefulShellRoute
with BestieTabBar so Profil + Undangan + Home share one shell.

- Shell: features/shell/ (StatefulShellRoute, BestieTabBar, 3 branches)
- Undangan: features/undangan/ — Curhat Baru reads
  chatRequestProvider.pendingInvites; row Terima delegates accept to
  the notifier and ChatRequestOverlay owns nav (no double-push).
  Perpanjang tab stubbed (empty state) until backend exposes
  pendingExtensionsProvider.
- Profil: features/profile/ — Bestie-styled stub
- Home: refactored to body-only (shell owns chrome)
- Popup: chat_request_overlay + chat_request_notifier updated to
  serve the list rows, not just the modal
- Chat: mitra_chat_screen polish
- Theme: accentAmber tokens for the Perpanjang tab + halo_orb widget
  (loading spinner used by undangan list states)
- Login: replace broken GoRouterState location guard with
  _expectOtpPush flag — was stacking duplicate /otp pages on OTP
  resend (see project-otp-nav-bug-fixed-2026-05-21)

Maestro:
- 17 new flows under .maestro/flows/ts-mitra-{1,2,3}-* covering home
  online/offline variants, undangan empty/populated/tolak states,
  popup curhat-baru → accept → chat → ended banner, plus popup
  dismiss/expire/cancelled edge cases
- 4 new §A OTP flows (07/08/09/10) for invalid/mismatch/expired/cooldown
- Helper scripts: force_mitra_online/offline, force_pairing_timeout,
  force_session_expires_at, delete_mitra_status_row,
  customer_blast_now (js), customer_cancel_latest_blast
- Backend: POST /internal/_test/delete-mitra-status-row supports the
  "fresh mitra with no status row" test setup

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

backend/src/routes/internal/_test.routes.js

@@ -442,6 +442,26 @@ export const internalTestRoutes = async (fastify) => {
     return { ok: true, ...updated }
   })
 
+  // Delete the mitra_online_status row for a given mitra — used by Maestro
+  // scenario flows that need to simulate a "freshly created mitra with NO
+  // status row yet" (the natural state right after seed_mitra and before
+  // any /api/mitra/status call from the app). The app's first /status call
+  // re-creates the row via ensureStatusRow() with the DB default
+  // is_online=false; this endpoint just rewinds to that pre-state.
+  //
+  // Body: { mitra_id }
+  fastify.post('/delete-mitra-status-row', async (request, reply) => {
+    const mitraId = request.body?.mitra_id
+    if (!mitraId) {
+      return reply.code(400).send({ error: 'mitra_id required in body' })
+    }
+    const result = await sql`
+      DELETE FROM mitra_online_status WHERE mitra_id = ${mitraId}
+      RETURNING mitra_id
+    `
+    return { ok: true, mitra_id: mitraId, deleted: result.length > 0 }
+  })
+
   // Accept the most recent pending pairing notification, regardless of which
   // mitra it was sent to. Used by Maestro flows where the test doesn't know
   // (or care) which specific mitra should accept — e.g. TS-02 (blast where