feat(gateway): temporary IP ban (fail2ban) fed by rejections + honeypot/honeytoken

Add a prod-only, in-memory IP ban enforced at the edge, fed by three signals:
sustained rate-limiter rejections (the IP-keyed public/email/admin classes — the
user class stays the backend soft-flag's concern), a honeypot decoy-path hit (the
contour caddy tags decoys with X-Scrabble-Honeypot and routes them to the gateway),
and a honeytoken (a planted bearer, GATEWAY_HONEYTOKEN). A banned IP is refused with
429 by the abuseGuard middleware before any work — covering the Connect edge, the
live stream and the static SPA/landing the per-op limiter never gated.

The ban is off by default: it keys by the real client IP the shared-NAT test contour
does not expose, so a ban there would be self-inflicted; detection still logs in the
contour, only the ban action is gated (GATEWAY_ABUSE_BAN_ENABLED). Rejection bans last
GATEWAY_ABUSE_BAN_DURATION; tripwire/honeytoken hits are near-zero-false-positive and
earn longer fixed bans. Each ban increments gateway_abuse_banned_total{reason}.

Operators see and lift active bans on the admin console's Throttled page; the gateway
syncs its active set to the backend every 30s (POST /api/v1/internal/bans/sync,
backend/internal/banview) and applies the operator unbans the response returns.

PRERELEASE phase AG. Docs baked into ARCHITECTURE / FUNCTIONAL (+ru) / both READMEs.

PRERELEASE.md

@@ -40,6 +40,7 @@ the edge before prod. Each phase maps back to the owner's raw pre-release TODO l
 | SB | Single Telegram bot + per-user variant preferences: the two per-language bots collapse into **one** (drop `accounts.service_language`, `supported_languages`, the `*_EN`/`*_RU` env vars and game-language push routing — the single bot renders in the recipient's `preferred_language`); New Game variant gating moves to a profile **`variant_preferences`** set (default Erudit only, Erudit-first, server-enforced on the caller's auto-match/vs-AI/invitation-create paths, an invited friend may accept any variant); env vars collapse to unsuffixed `TELEGRAM_BOT_TOKEN`/`TELEGRAM_GAME_CHANNEL_ID`/`VITE_TELEGRAM_LINK`/`VITE_TELEGRAM_GAME_CHANNEL_NAME` and `GATEWAY_DEFAULT_SUPPORTED_LANGUAGES` is removed; wire drops `service_language`/`supported_languages` (Session, ValidateInitDataResponse) + the push `language` routing field and adds `variant_preferences` to Profile/UpdateProfile. | owner ad-hoc | **done** |
 | DV | Dictionary version hygiene: CI + image/compose seed track the current release (`v1.2.1`); a **seed-drift guard** records the flat dir's seed in an authoritative `.seed_version` marker so a bumped build seed on a live volume is ignored (it can't relabel live bytes — which would mis-serve the dictionary + void games pinned to the prior label); `DICT_VERSION` is the fresh-volume seed only, a live contour migrates through the admin console | owner ad-hoc | **done** |
 | TX | Telegram egress off the main host: split the connector into a home **validator** (Mini App / Login-Widget HMAC, no VPN, no Bot API — so game login no longer depends on Telegram being reachable) and a remote **bot** (Bot API long-poll + `sendMessage`) that holds **no inbound port** and dials the gateway over a reverse **mTLS bot-link** (`pkg/proto/botlink/v1`); the gateway funnels out-of-app push (fire-and-forget, at-most-once) and the backend admin broadcasts (a relay that awaits the bot's ack) down the link. The bot is Telegram-rate-limited; **one bot now**, with seams (a bot registry + `owns_updates` + command ids) for N later; **no webhook** (rejected: one URL per token, adds inbound + a static address). The **unified test contour** runs the split (the bot keeps its VPN sidecar and dials the gateway by its internal name; certs from `deploy/gen-certs.sh`). The **prod** wiring — the bot on a separate host (no VPN), the gateway bot-link port published, `PROD_` certs with scheduled rotation, an SSH deploy of both hosts together — is the **deferred final stage** (Stage 18). | owner ad-hoc | **done** (code + test contour; prod wiring → Stage 18) |
+| AG | Anti-abuse IP ban + honeypot/honeytoken (prod-only): a fail2ban-style in-memory `ratelimit.Banlist` keyed by client IP, fed by sustained rate-limiter rejections (the IP-keyed public/email/admin classes — the user class stays the soft-flag's concern), a **honeypot** decoy path (the contour caddy tags `/.env`, `/.git`, `/wp-*`, … with `X-Scrabble-Honeypot` and routes them to the gateway), and a **honeytoken** (`GATEWAY_HONEYTOKEN`, a planted bearer). The `abuseGuard` edge middleware refuses a banned IP with **429** before any work — closing the R3 gap that the static SPA/landing was outside the token bucket. Off by default — it keys by the real client IP the shared-NAT test contour does not expose (detection still logs there); enabled in prod via `GATEWAY_ABUSE_BAN_ENABLED`. Operators see + lift bans on the console **Throttled** page; the gateway syncs its active set to the backend (`/api/v1/internal/bans/sync`, `internal/banview`) every 30 s and applies operator unbans. | owner ad-hoc | **in progress** |
 | → | Stage 18 — prod contour deploy | — | see [`PLAN.md`](PLAN.md) |
 
 ## Key findings (these reshaped the raw list — read before starting a phase)
@@ -83,6 +84,19 @@ the edge before prod. Each phase maps back to the owner's raw pre-release TODO l
 - **Rate-abuse (TODO 8):** metric + Grafana + admin view **plus a conservative auto-flag** —
   a *soft, reversible* "suspected high-rate" marker for operator review, tunable threshold,
   **no auto-ban**.
+- **Anti-abuse IP ban (AG, owner ad-hoc):** a honeypot was considered and rejected as a *DDoS*
+  defence — it detects/deceives but does not shed volumetric load, cannot cover the real
+  endpoints, and a tarpit backfires under flood; volumetric L3/L4 is an upstream/CDN concern,
+  out of scope. The effective layer is a **temporary IP ban** (fail2ban-style) that the honeypot
+  and honeytoken merely *feed*. This does **not** reverse the TODO-8 "no auto-ban": that decision
+  governs the **account** soft-flag (still never a gate); the IP ban is a separate, IP-keyed,
+  **prod-only** layer with an **operator unban** in the console. Decisions: banlist lives in the
+  existing `ratelimit` package (smallest surface); the decoy path list is a **single source of
+  truth in the caddy** (it tags requests with a header — the gateway keeps no second list);
+  bans are in-memory + single-instance (like `ratewatch`), auto-expiring, **plus** an admin
+  console view + manual unban over a bidirectional 30 s sync (operator control = owner's choice).
+  An active-bans Grafana **gauge** was trimmed (the console view + the `gateway_abuse_banned_total`
+  counter cover it) to keep the diff focused.
 - **Open auto-match (owner ad-hoc):** a quick game **enters a real game at once and waits inside
   it** (status `open`, the opponent seat empty); a second human searching the same variant+rule
   joins it, or a robot fills it after a **90 s + random 0–90 s** wait, pushing the in-app