[codex] Polish subscriptions, email layout and resubscription

AGENTS.md

@@ -8,9 +8,10 @@ public engineering records with dated evidence, not live configuration.
 
 - Continue the existing bilingual Generative UI newsroom, atlas and academy.
   Preserve the existing Sites project, public domain and old routes.
-- The October 13, 2026 handoff records production v12 and public email as
-  enabled. Earlier v5 reports and pre-activation examples are historical.
-  Do not re-enable or disable production email based on those examples.
+- The October 13, 2026 v12 handoff and subsequent v1.0.0 release record public
+  email as enabled. Use the dated public release records to distinguish
+  production from a newer candidate. Earlier v5 reports and pre-activation
+  examples are historical; do not toggle production email based on them.
 - Inspect the actual checkout, local changes, latest remote and current PR
   before Git changes. Preserve user work and remote commits; use a suitable
   existing worktree. Never silently stash, clean, reset or force-push.
@@ -23,18 +24,30 @@ public engineering records with dated evidence, not live configuration.
 - GitHub merge does not deploy Sites. Reuse the existing project identity in
   `.openai/hosting.json`; public-launch DNS rollback records are historical and
   must not be applied to the current subscription-enabled service.
-- Respect the current user-authorized scope. The v12 handoff/synchronization
-  covers GitHub and public documentation only, without deployment, DNS,
-  production configuration, schedule changes or real mail.
+- Respect the current user-authorized scope. The historical v12 GitHub
+  synchronization did not authorize deployment, DNS, configuration, schedule
+  changes or real mail. Later authorization is recorded separately; a local
+  candidate, GitHub merge or documentation change is not a Sites deployment.
 - Keep private handoff/audit materials outside the public repository. Do not
   read or copy secret values, private mailboxes, subscriber data, signed links
   or browser sessions into documentation, logs or commits.
 - Use isolated local D1 and a local Worker for HTTP tests. Keep local mail
   flags false and use no real keys. Never use production as the test target,
   impersonate an owner, or invoke `mail-test` from editorial schedules.
-- Preserve active POST confirmation/unsubscribe, capacity enforcement, test
-  isolation, generation/epoch guards, idempotency and suppression. Keep
-  provider submission distinct from delivery and inbox acceptance.
+- Confirmation uses a same-origin POST automatically only when its signed
+  confirmation page is visible, non-prerendered and ready. Attempt at most
+  once per mount; a language remount may retry idempotently. GET, HEAD, SSR
+  and HTTP preload do not confirm. A JavaScript-capable bot can mimic a visible
+  page; never claim visibility proves a human or prevents every scanner.
+- Cancellation and unsubscribe still require an explicit reader POST. Preserve
+  capacity, test isolation, generation/epoch guards, old-request cancellation,
+  idempotency and suppression. Public unsubscribed recipients may begin a new
+  cycle only through fresh valid consent and monotonically newer link clocks;
+  never use public signup to revive suppressed/test identities, historical hard
+  failures or unknown submissions. Do not reset quotas or purchase allowance.
+  Keep provider submission
+  distinct from delivery and inbox acceptance. Candidate details are in
+  [the subscription iteration](docs/iterations/2026-10-13-subscription-polish.md).
 - Preserve accurate tracking and network disclosures. Anonymous Brevo
   tracking is not proof that pixels/rewritten links are disabled. Mainland
   accessibility is not guaranteed.