docs: ship in-house RN checkout, scope 5 follow-up tasks (#7-11)

In-house Request Network checkout went fully end-to-end on dev today.
A real 0.01 USDC payment flowed through wallet connect -> approve ->
ERC20FeeProxy.transferFromWithReferenceAndFee -> RN webhook ->
TransactionSafetyProvider -> Payment.status=completed -> page success
state. Tx 0x494c77a29161b5100d8e0b1ac675f1822955d0bb3633ecdbfafb886f84f2f320.

Docs:
- New PRD: Wallet, Multichain, Confirmations, AML, Trezor
  (5 follow-ups, each sized for an independent contributor)
- Updated PRD: Request Network In-House Checkout (phases 0..3 done,
  phase 4 partial, phases 5-6 not started)
- Updated handoff: deployed versions, what is working end-to-end,
  follow-up tasks index

Taskmaster: 5 new top-level tasks (#7..#11) covering ephemeral
destination wallets, multichain proxy registry + USDC/USDT, runtime
confirmation thresholds, optional seller-paid AML screening, and
Trezor signing for admin actions. Tasks are scoped fine-grained so
each is independent enough for kimi to pick up.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

08 - Operations/Incident Response.md

@@ -260,6 +260,20 @@ If user data may have leaked, treat as sev 1 and follow your data-breach disclos
 
 Use when Request Network payments are failing, stalled, or out of sync with local payment state.
 
+**First triage:**
+
+1. Check whether RN reached nginx:
+
+   ```bash
+   grep '/api/payment/request-network/webhook' /opt/backend/nginx/logs/access.log | tail -50
+   ```
+
+2. If RN deliveries returned `404`, treat it as a backend correlation/config bug. Do not run another paid probe until the correlation fix is deployed and smoke-tested.
+
+3. If deliveries returned `202` or `200` but the payment is still pending, inspect `metadata.transactionSafety` on the `Payment` document. A safety-pending payment is captured but not credited; look for missing tx hash, insufficient confirmations, transfer mismatch, or AML provider blockers.
+
+4. If Cloudflare Worker durable ingress is enabled, replay from the Worker delivery id/time window after backend repair instead of asking the buyer to pay again.
+
 **Immediate rollback (minutes):**
 
 1. Stop routing new intents to Request Network by setting: