release: v0.51.31 — Release H (12-PR contributor batch)

CHANGELOG, ROADMAP, TESTING refresh for v0.51.31 stage release covering
12 contributor PRs:

Added (2 PRs):
- #1956 JKJameson — persistent composer draft (server-side, cross-client)
- #1957 hermes-gimmethebeans — configurable session TTL via env + settings

Fixed (10 PRs):
- #1939 ai-ag2026 — theme-color + sw cache regression coverage
- #1941 ai-ag2026 — preserve chat scroll across final render
- #1945 franksong2702 — localize session jump controls (#1938)
- #1947 happy5318 — show same model from different custom providers
  (Co-authored-by hacker1e7 for #1874 close)
- #1949 Sanjays2402 — close #1937 endless-scroll vs Start-jump race
  with generation-token + mutex
  (Co-authored-by franksong2702 + Michaelyklam)
- #1950 franksong2702 — mute stale stopped gateway heartbeat (#1944)
- #1951 amlyczz — gate goal hook on goal-related turns (#1932)
  (Co-authored-by franksong2702 for #1946 close)
- #1953 lucky-yonug — skip provider peel for custom host:port slugs
- #1960 Michaelyklam — translate hidden-files workspace label (#1841)
- #1961 sbe27 — respect image_input_mode (#1959)

Closed in favor of canonical: #1942, #1962, #1946, #1874, #1311.

Stage-326 hotfixes (per Opus advisor):
- CRITICAL #1951 PENDING_GOAL_CONTINUATION race fix (removed finally
  discard that race-erased the marker before consumer could read it)
- #1956 composer-draft input validation (50 KB text / 50 file clamp +
  type coercion to prevent unbounded session-JSON bloat)
- #1957 SESSION_TTL constant preserved as named fallback (existing
  regression tests pin it; #1957 originally deleted it)

Tests: 5006 → 5028 (+51 net new) — 0 regressions, 142.61s runtime.

ROADMAP.md

@@ -2,7 +2,7 @@
 
 > Web companion to the Hermes Agent CLI. Same workflows, browser-native.
 >
-> Last updated: v0.51.30 (May 8, 2026) — 4977 tests collected — 3-PR Release G batch (offline recovery + PWA hardening + opt-in session jump buttons + opt-in endless-scroll)
+> Last updated: v0.51.31 (May 9, 2026) — 5028 tests collected — Release H 12-PR contributor batch (image-mode fix + race fixes + composer drafts + locale parity + custom-provider dedup + TTL config + heartbeat polish)
 > Test source: `pytest tests/ --collect-only -q`
 > Per-version detail: see [CHANGELOG.md](./CHANGELOG.md)