Expand ROUTE_GUARD_TIERS.md Tier 1 (LOCAL_ONLY):
- link the GHSA advisory and explain the attack class (RCE via a subprocess spawn
reachable from non-loopback traffic)
- replace the 3-example prefix table with the full LOCAL_ONLY set, mirroring
LOCAL_ONLY_API_PREFIXES / LOCAL_ONLY_API_PATTERNS in routeGuard.ts (the
authoritative source; check-route-guard-membership enforces the code side)
- add an "Operator guidance & auditing" section for users behind
nginx/Cloudflare/Tailscale: don't forge X-Forwarded-For loopback, keep the
manage-scope bypass minimal, and how to audit non-loopback access
Docs-only; SECURITY.md already links here.
Closes#5599
Evolves the cache-aware guard to also learn which system prompts recur: observed >= threshold → treated as a stable cacheable prefix and preserved even for providers the static check misses. Content-addressed by a hash of the system prompt (OpenAI/Claude/Gemini), in-memory, freeze=preserve (never mutates). Opt-in/default-off (COMPRESSION_PREFIX_FREEZE_ENABLED); respects the never preserve-mode. New prefixFreeze.ts wired into resolveCacheAwareConfig. Regression guard: prefix-freeze.test.ts (10); 44 cache-aware tests green. gaps v3.8.42 — T08/H5 (2.4).
Integrated into release/v3.8.43. Includes the legacy-boolean back-compat derivation so existing preserveSystemPrompt=false installs keep whenNoCache behavior.
v3.8.40 cycle integration → main. All test gates green (Unit/Integration/Coverage/Node-compat/Quality-Ratchet). The only red check, 'PR Test Policy', is the test-masking heuristic firing on the cumulative ~57-commit release diff (legitimate assert consolidations already reviewed per-PR — Gemini CLI removal #5246, retired GPT models #5280, provider catalog refreshes); overridden with --admin per the documented release-PR convention. CodeQL/SonarQube advisory scans non-blocking; #5278's code already passed CodeQL on main. Homologated on VPS 192.168.0.15 (v3.8.40 healthy).
