feat: add bounded control plane rate limiting

multiplayer-todo.md

@@ -1184,7 +1184,7 @@ the local/CI/community transport, not a silent production fallback.
 | 8.9 `[D:8.4,8.7]` | **IN PROGRESS.** Pure Go join policy binds SteamID/player/match/server/team/slot/protocol/expiry, rejects duplicate roster slots, permits same-identity reclaim through backend loss and fences prior server-owned generations | `server/domain/reconnect.go` covers SteamID/server/slot binding, expiry, repeated reclaim, grace boundary and old-generation fencing; signed token issuance/verification, persistent leases, Godot `hello` transport and production integration remain |
 | 8.10 `[D:8.5,8.31]` | **IN PROGRESS.** Dependency-free workload credential policy validates an adapter-verified signature, issuer/audience/time bounds, namespace/service account, pod UID, GameServer UID, allocation ID, match ID and server ID before result submission | `server/domain/workload.go` and adversarial tests reject every binding mutation, missing/unverified signature and time boundary; `server/testkit/pipeline_test.go` carries allocation identity through the offline result path; projected-token/JWT adapter, trusted-cluster verification and live duplicate/conflict alerting remain |
 | 8.11 `[D:8.1]` | **DONE.** Write the threat model: forged clients/replay/queues/results, floods/bots, pod/insider compromise, gameplay and API DDoS, SDR signing-key theft, dependencies and denial-of-wallet | [`docs/THREAT-MODEL.md`](docs/THREAT-MODEL.md) records prevention, detection/response, owner and residual risk for every threat; it separates offline CA/online signer, client/game-server/PostgreSQL/Redis trust boundaries and recovery behavior |
-| 8.12 `[D:8.11]` | **IN PROGRESS.** Provider-neutral Kubernetes baseline enforces restricted namespace admission, non-root/read-only/no-capability workloads, separate service accounts, allocator-only RBAC, default-deny networking and explicit edge/data/DNS/Agones flows; application manifests consume externally populated Secret objects | `deploy/k8s/base/` plus `server/security/test_kubernetes_policies.py` cover the static hardening and secret-reference invariants; private-store provisioning, edge DDoS/WAF/origin shielding, WebSocket limits, overload shedding, encrypted backups and live policy/load tests remain |
+| 8.12 `[D:8.11]` | **IN PROGRESS.** Provider-neutral Kubernetes baseline enforces restricted namespace admission, non-root/read-only/no-capability workloads, separate service accounts, allocator-only RBAC, default-deny networking and explicit edge/data/DNS/Agones flows; application manifests consume externally populated Secret objects; the Go API now has an optional bounded per-replica rate-limit/429 boundary | `deploy/k8s/base/` plus `server/security/test_kubernetes_policies.py`, `server/api/rate_limit.go` and adversarial tests cover static hardening, secret-reference invariants, fixed-window limits and bounded key memory; private-store provisioning, distributed/global quotas, edge DDoS/WAF/origin shielding, WebSocket limits, overload shedding, encrypted backups and live policy/load tests remain |
 | 8.13 `[D:8.12]` | **IN PROGRESS.** Docker/Kubernetes references are digest-pinned, a dependency-free checker rejects mutable tags/plaintext credentials and concrete release overlays can reject template digests; release documentation defines SBOM, dependency/image scanning, signing, admission verification and a 24-hour critical-fix SLA | `scripts/verify_supply_chain.py`, `server/security/test_supply_chain.py`, `docs/SUPPLY-CHAIN.md` and `.github/workflows/supply-chain.yml` cover repository policy and provenance requirements; registry SBOM/scan/sign/admission execution and a concrete production overlay remain |
 
 #### 8C — Queueing, matchmaking, playlists and rating