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().

static/i18n.js

@@ -195,6 +195,7 @@ const LOCALES = {
     settings_label_language: 'Language',
     settings_label_token_usage: 'Show token usage',
     settings_label_sidebar_density: 'Sidebar density',
+    cmd_reasoning: 'Toggle thinking block visibility (show/hide) or set effort level',
     settings_label_cli_sessions: 'Show agent sessions',
     settings_label_sync_insights: 'Sync to insights',
     settings_label_check_updates: 'Check for updates',
@@ -626,6 +627,7 @@ const LOCALES = {
     settings_label_language: 'Язык',
     settings_label_token_usage: 'Показывать использование токенов',
     settings_label_sidebar_density: 'Плотность боковой панели',
+    cmd_reasoning: 'Toggle thinking block visibility (show/hide) or set effort level',
     settings_label_cli_sessions: 'Показывать сеансы агента',
     settings_label_sync_insights: 'Синхронизировать с Insights',
     settings_label_check_updates: 'Проверять обновления',
@@ -1085,6 +1087,7 @@ const LOCALES = {
     settings_label_language: 'Idioma',
     settings_label_token_usage: 'Mostrar uso de tokens',
     settings_label_sidebar_density: 'Densidad de la barra lateral',
+    cmd_reasoning: 'Toggle thinking block visibility (show/hide) or set effort level',
     settings_label_cli_sessions: 'Mostrar sesiones de CLI',
     settings_label_sync_insights: 'Sincronizar con insights',
     settings_label_check_updates: 'Buscar actualizaciones',
@@ -1516,6 +1519,7 @@ const LOCALES = {
     settings_label_language: 'Sprache',
     settings_label_token_usage: 'Token-Verbrauch anzeigen',
     settings_label_sidebar_density: 'Seitenleistendichte',
+    cmd_reasoning: 'Toggle thinking block visibility (show/hide) or set effort level',
     settings_label_cli_sessions: 'Agent-Sitzungen anzeigen',
     settings_label_sync_insights: 'Mit Insights synchronisieren',
     settings_label_check_updates: 'Nach Updates suchen',
@@ -1748,6 +1752,7 @@ const LOCALES = {
     settings_label_language: '\u8bed\u8a00',
     settings_label_token_usage: '\u663e\u793a token \u7528\u91cf',
     settings_label_sidebar_density: '侧边栏密度',
+    cmd_reasoning: 'Toggle thinking block visibility (show/hide) or set effort level',
     settings_label_cli_sessions: '\u663e\u793a CLI \u4f1a\u8bdd',
     settings_label_sync_insights: '\u540c\u6b65\u5230 insights',
     settings_label_check_updates: '\u68c0\u67e5\u66f4\u65b0',
@@ -2163,6 +2168,7 @@ const LOCALES = {
     settings_label_language: '\u8a9d\u8a00',
     settings_label_token_usage: '\u986f\u793a token \u7528\u91cf',
     settings_label_sidebar_density: '側邊欄密度',
+    cmd_reasoning: 'Toggle thinking block visibility (show/hide) or set effort level',
     settings_label_cli_sessions: '\u986f\u793a CLI \u6703\u8a71',
     settings_label_sync_insights: '\u540c\u6b65\u5230 insights',
     settings_label_check_updates: '\u6aa2\u67e5\u66f4\u65b0',