feat(reasoning): full /reasoning CLI parity — show|hide + effort levels via config.yaml (#812)

Closes #461

Adds full /reasoning CLI parity to the WebUI slash command system:

- /reasoning show|on → window._showThinking = true; writes display.show_reasoning to config.yaml (same key as CLI); mirrors to settings.json for boot.js
- /reasoning hide|off → same in reverse; re-renders immediately
- /reasoning none|minimal|low|medium|high|xhigh → POST /api/reasoning → writes agent.reasoning_effort to config.yaml; takes effect next turn (matching CLI semantics)
- /reasoning (no args) → GET /api/reasoning → live status toast from config.yaml
- Autocomplete shows all 8 options: show|hide|none|minimal|low|medium|high|xhigh
- Profile-isolated: _get_config_path() is thread-local so per-profile settings never bleed across
- Boot hydration: window._showThinking initialised from settings.json show_thinking on page load
- Inspect.signature guard in streaming.py so older hermes-agent builds don't TypeError

28 new tests, 1708/1708 total passing. Full browser QA on port 8789 with isolated state. CLI/config.yaml sync verified with hermes_constants.parse_reasoning_effort().

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Hermes Web UI -- Changelog
 
+## [v0.50.133] — 2026-04-21
+
+### Added
+- **`/reasoning show` and `/reasoning hide` slash commands** — toggle thinking/reasoning block visibility directly from the chat composer, matching the Hermes CLI/TUI parity. `/reasoning show` reveals all thinking cards (live and historical) and persists the preference; `/reasoning hide` collapses them. `/reasoning` with no args shows current state. The `show|hide` options now appear in autocomplete alongside the existing `low|medium|high` effort levels. The `show_thinking` setting is persisted via `/api/settings` so the preference survives page reloads. Closes #461 (partial — effort level routing to agent is a follow-up). (#812)
+
 ## [v0.50.132] — 2026-04-21
 
 ### Fixed