feat: add tags, configurable tabs, and tag-based filtering

- Add `tags` field to LaunchItem for categorization
- Extract .desktop Categories as tags for applications
- Add semantic tags to providers (systemd, ssh, script, etc.)
- Display tag badges in result rows (max 3 tags)
- Add `tabs` config option for customizable header tabs
- Dynamic Ctrl+1-9 shortcuts based on tab config
- Add `:tag:XXX` prefix for tag-based filtering
- Include tags in fuzzy search with lower weight
- Update config.example.toml with tabs documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

data/config.example.toml

@@ -13,6 +13,10 @@ terminal_command = "kitty"  # Auto-detected if not set
 #   ""                         # Direct execution
 # launch_wrapper = "uwsm app --"
 
+# Provider tabs shown in header bar (Ctrl+1, Ctrl+2, etc. to toggle)
+# Valid values: app, cmd, uuctl, bookmark, calc, clip, dmenu, emoji, file, script, ssh, sys, web
+tabs = ["app", "cmd", "uuctl"]
+
 [appearance]
 width = 600
 height = 400