incidents: add the 2026-10-02 gateway outage write-up (from the unmerged incident branch)

The write-up has sat on incident/2026-10-02-gateway-cve-upgrade since the
outage and that branch is now far behind main. This lifts just the incident
text and the CVE note into incidents/, attributed to InferenceBot with the
substance unchanged, and links it from infrastructure.md under a new
Incident log section.

incidents/2026-10-02-gateway-cve-upgrade.md

@@ -0,0 +1,34 @@
+# 2026-10-02 — gateway outage after a security-upgrade rebuild
+
+*Written by InferenceBot on the `incident/2026-10-02-gateway-cve-upgrade`
+branch on 2026-10-01; moved to `main` with the substance unchanged so it's
+findable.*
+
+**Impact.** The gateway (chat and API) was down about 50 minutes,
+04:50–05:34 UTC. No data loss.
+
+**What happened.** A Cloudron update triggered by a member's CVE report
+rebuilt the app image. The Dockerfile pinned the floating
+`main-v1.74.0-stable` tag, which the registry had silently moved to newer
+(v1.84.0-era) bits, so the rebuild changed the running version and kicked
+off a full Prisma database migration that takes 10–15 minutes per boot with
+internal timeouts and retries. The migration ran at Cloudron's default
+256 MB memory cap and was OOM-killed; the app crash-looped on a missing
+migrations ledger until the memory limit and `LITELLM_MIGRATION_DIR` were
+fixed.
+
+**Also during the incident.** The domain's authoritative nameservers
+(yoursrs.com) were intermittently unreachable, briefly failing resolution of
+some hostnames (git, portal). Transient, registrar-side, self-recovered; no
+records were wrong. The upgrade had also silently reverted CORS to `*`.
+
+**Repairs.** Version pinned to the exact tag in `code/litellm`;
+`memoryLimit` set to 2 GB in the manifest; `LITELLM_MIGRATION_DIR` pointed
+at the persistent volume; `LITELLM_CORS_ORIGINS` set to the chat origin;
+packaging synced to mirror the live deployment. The upgrade rules learned
+here are in the `code/litellm` README under "Updating LiteLLM".
+
+**What it fixed on the security side.** CVE-2026-35029 (authorization bypass
+on `/config/update`, fixed in 1.83.0) and CVE-2026-59822 (MCP session auth
+bypass, fixed in 1.84.0, listed in CISA's Known Exploited Vulnerabilities
+catalog). The gateway has since moved to v1.103.2.