feat(skill): add multi-app skill support for Claude/Codex (#365)

* feat(skill): add multi-app skill support for Claude/Codex/Gemini

- Add app-specific skill management with AppType prefix in skill keys
- Implement per-app skill tracking in database schema
- Add get_skills_for_app command to retrieve skills by application
- Update SkillsPage to support app-specific skill loading with initialApp prop
- Parse app parameter and validate against supported app types
- Maintain backward compatibility with default claude app

* fix(usage): reorder cache columns and prevent header text wrapping

- Swap cache read and cache write columns order
- Add whitespace-nowrap to all table headers to prevent text wrapping
- Improves table readability and layout consistency

src-tauri/src/lib.rs

@@ -635,8 +635,11 @@ pub fn run() {
             commands::restore_env_backup,
             // Skill management
             commands::get_skills,
+            commands::get_skills_for_app,
             commands::install_skill,
+            commands::install_skill_for_app,
             commands::uninstall_skill,
+            commands::uninstall_skill_for_app,
             commands::get_skill_repos,
             commands::add_skill_repo,
             commands::remove_skill_repo,