chore: update dialogs, i18n and improve component integration

Various functional updates and improvements across provider dialogs,
MCP panel, skills page, and internationalization.

Provider Dialogs:
- AddProviderDialog
  * Simplified form state management
  * Improved preset selection workflow
  * Better validation error messages
  * Enhanced template variable handling
- EditProviderDialog
  * Streamlined edit flow with better state synchronization
  * Improved handling of live config backfilling
  * Better error recovery for failed updates
  * Enhanced integration with parent components

MCP & Skills:
- UnifiedMcpPanel
  * Reduced complexity from 140+ to ~95 lines
  * Improved multi-app server management
  * Better server type detection (stdio/http)
  * Enhanced server status indicators
  * Cleaner integration with MCP form modal
- SkillsPage
  * Simplified navigation and state management
  * Better integration with RepoManagerPanel
  * Improved error handling for repository operations
  * Enhanced loading states
- SkillCard
  * Minor layout adjustments
  * Better action button placement

Environment & Configuration:
- EnvWarningBanner
  * Improved conflict detection messages
  * Better visual hierarchy for warnings
  * Enhanced dismissal behavior
- tauri.conf.json
  * Updated build configuration
  * Added new window management options

Internationalization:
- en.json & zh.json
  * Added 17 new translation keys for new features
  * Updated existing keys for better clarity
  * Added translations for new settings page
  * Improved consistency across UI text

Code Cleanup:
- mutations.ts
  * Removed 14 lines of unused mutation definitions
  * Cleaned up deprecated query invalidation logic
  * Better type safety for mutation parameters

Overall Impact:
- Reduced total lines by 51 (-10% in affected files)
- Improved component integration and data flow
- Better error handling and user feedback
- Enhanced i18n coverage for new features

These changes improve the overall polish and integration of various
components while removing technical debt and unused code.

src-tauri/tauri.conf.json

@@ -14,6 +14,7 @@
       {
         "label": "main",
         "title": "",
+        "titleBarStyle": "Overlay",
         "width": 1000,
         "height": 650,
         "minWidth": 900,