Phase 4 checkpoint: chat-screen perf refactor + retryable blast-failure + repo-wide dispose-ref guardrail

Chat-screen performance (customer + mitra):
- Parent screens have zero `ref.watch` — only `ref.listen` for side effects
- Body extracted into its own `ConsumerStatefulWidget`; AppBar parts split
  into narrow `.select` consumers (mode, sensitivity, timer)
- Per-second timer ticks routed to dedicated providers
  (`chatRemainingSecondsProvider` + new `mitraChatRemainingSecondsProvider`)
  so WS `session_tick` frames don't invalidate the rest of the chat state

Dispose-in-ref bug fix:
- `home_screen.dart`, `payment_screen.dart`, `mitra_chat_screen.dart` —
  ref-using cleanup moved from `dispose()` to `deactivate()`. Modern
  Riverpod invalidates `ref` the moment `dispose()` runs; the resulting
  silent error corrupts the widget-tree finalize and the next screen
  appears frozen
- `halo_lints` package added at repo root with `no_ref_in_dispose` rule
  to catch this pattern in CI / IDE analysis
- `custom_lint` activated in both apps' `analysis_options.yaml`
  (was installed but never wired in — also brings `riverpod_lint`'s
  `avoid_ref_inside_state_dispose` online)
- CLAUDE.md Pitfalls section added to client_app + mitra_app

Phase 4 §3 retryable blast-failure (Option A):
- Backend `expirePairingRequest` + all-rejected use
  `recordIntermediateFailure` instead of `failPaymentSession` so the
  payment session stays `confirmed` for re-blast
- WS `pairing_failed` payload carries `is_terminal: false` on the
  retryable paths; client parses the flag and exposes `retryBlast()`
- "Coba cari lagi" CTA on S7 Timeout now re-blasts on the same payment
- Pairing service test updated to reflect the new semantics

Customer waiting-payment screen navigation patch:
- `_navigateTerminal` uses `Future.microtask` + `addPostFrameCallback`
  redundancy after a release-mode bug where polling stopped but
  `context.go` never fired, leaving the screen visually stuck on
  "menunggu pembayaran"

See requirement/resume-2026-05-15.md for next-day pickup checklist
(mitra release rebuild + S21 Ultra install + retest is the gating item).

Bundles unrelated in-flight Phase 4 §2.x work that was already on disk
(ESP screen removal, USP one-time gate scaffolding, bestie-availability
public route, OTP service edits, Maestro flow tweaks) — kept together
to avoid a partial-rebase mess.

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

client_app/lib/features/auth/widgets/otp_blocked_popup.dart

@@ -7,8 +7,12 @@ import '../../support/widgets/tanya_admin_sheet.dart';
 /// Modal shown when OTP delivery / verification is exhausted (rate-limited
 /// 429 from `OTP_RATE_LIMIT_PHONE`, `OTP_RATE_LIMIT_IP`, `OTP_COOLDOWN`, or
 /// `OTP_ATTEMPTS_EXCEEDED`). Offers a "lanjut tanpa verif" exit into the
-/// anonymous flow (preserving any ESP/USP state) and a "hubungi admin" CTA
-/// that opens the Tanya Admin sheet.
+/// anonymous flow and a "hubungi admin" CTA that opens the Tanya Admin sheet.
+///
+/// By the time this popup can fire, the USP one-time gate has already been
+/// evaluated upstream on `VerifChoiceSheet` (either shown + marked seen, or
+/// skipped because already seen). The exit can therefore jump straight into
+/// `/payment/method-pick` regardless.
 class OtpBlockedPopup {
   const OtpBlockedPopup._();
 
@@ -35,12 +39,7 @@ class OtpBlockedPopup {
       ),
       primary: HaloPopupAction(
         label: 'lanjut tanpa verif',
-        onPressed: () {
-          // ESP/USP picks live in Riverpod providers (espSelectionProvider,
-          // espSkippedProvider) and survive this navigation — no need to pass
-          // them as `extra`.
-          context.go('/onboarding/anon/method');
-        },
+        onPressed: () => context.go('/onboarding/anon/method'),
       ),
       secondary: HaloPopupAction(
         label: 'hubungi admin',