chore(release): stamp v0.51.19 — 15-PR contributor sweep + 1 in-stage absorb

- 15 contributor PRs across backend (workspace, IPv6, bootstrap pair,
  named custom provider routing, quota cards, live Codex models),
  frontend (sessions trio: optimistic-row preservation, cross-surface
  continuation, session-owned approval prompts; ui trio: workspace
  metadata strip, error toast Copy + hover-pause, file picker + HTML
  preview interactions), streaming (workspace-prefix dedupe), and
  ops (workspace user-turn repair script).
- 1 in-stage absorb on api/config.py: gate _resolve_configured_provider_id
  alias resolution behind resolve_alias flag so resolve_model_provider
  preserves raw provider strings for #1625 _LOCAL_SERVER_PROVIDERS
  literal-match.
- 1 in-stage test absorb on test_bootstrap_discover_agent.py: pin
  Path.home() in isolation helper so PR #1817 tests don't pick up
  the dev machine's real ~/.hermes/hermes-agent.
- 4747 → 4790 collected (+43). 4776 pass + 11 skip + 1 xfail + 2 xpass.
- Browser API harness 11/11 green. JS syntax 5/5 clean.
- Opus advisor SHIP verdict, 0 MUST-FIX, 0 SHOULD-FIX in-release.

Closes #1792, #1795, #1796, #1800, #1806, #1807, #1694.

ROADMAP.md

@@ -2,7 +2,7 @@
 
 > Web companion to the Hermes Agent CLI. Same workflows, browser-native.
 >
-> Last updated: v0.51.18 (May 7, 2026) — 4747 tests collected — 5-PR batch (#1783, #1789, #1790, #1791, #1794)
+> Last updated: v0.51.19 (May 7, 2026) — 4790 tests collected — 15-PR contributor sweep (workspace-prefix triple, file-picker + IPv6 + bootstrap pair, named custom provider routing, quota cards, session ownership, sidebar continuation)
 > Test source: `pytest tests/ --collect-only -q`
 > Per-version detail: see [CHANGELOG.md](./CHANGELOG.md)