chore(release): stamp v0.51.14 — 4-PR contributor batch (#1756, #1757, #1760, #1761)

Constituent PRs:
- #1760 (@ai-ag2026) preserve pending user turn on stream errors. Closes #1361.
- #1761 (@dso2ng) scope terminal stream cleanup to owner session. Refs #1694.
  AUTO-FIX applied: restored !INFLIGHT[S.session.session_id] disjunct in
  _setActivePaneIdleIfOwner (regression introduced by helper centralization).
- #1756 (@ng-technology-llc) isolate profile cookie per webui instance. Closes #803.
- #1757 (@skspade) tri-state gateway status (alive: True/False/None).

Tests: 4642 → 4662 collected (+20). 4649 passed, 9 skipped (test-isolation
prong-2 noise), 3 xpassed, 0 failed in 152s.

Pre-release verification:
- All 4 PRs CI-green or rebased clean (#1757 had stale base; CHANGELOG conflict
  auto-resolved by dropping the PR's redundant entry).
- node -c clean on static/messages.js + static/panels.js.
- 11/11 browser API endpoints PASS.
- Pre-stamp re-fetch: all PR heads match local rebases.
- Opus advisor: SHIP, all 5 verification questions clean, 0 MUST-FIX, 0 SHOULD-FIX.
- Two NICE-TO-HAVE coverage gaps absorbed in-release:
  (1) test_sprint36.py asserts !INFLIGHT[...] disjunct in helper body
  (2) test_issue1361_cancel_data_loss.py adds structural-grep test to pin
      _materialize_pending_user_turn_before_error call sites at error branches.

Closes #803, #1361, #1694.

ROADMAP.md

@@ -2,7 +2,7 @@
 
 > Web companion to the Hermes Agent CLI. Same workflows, browser-native.
 >
-> Last updated: v0.51.13 (May 6, 2026) — 4642 tests collected — single-PR composer UX (#1758)
+> Last updated: v0.51.14 (May 6, 2026) — 4662 tests collected — 4-PR contributor batch (#1756, #1757, #1760, #1761)
 > Test source: `pytest tests/ --collect-only -q`
 > Per-version detail: see [CHANGELOG.md](./CHANGELOG.md)