Add Fuse.js match highlighting to launcher search results

[skid-dev]

Motivation

• Improve launcher search UX by using Fuse.js match metadata to highlight matching characters in result titles and content previews with a yellow background.
• Use Fuse’s built-in match ranges so highlighting is accurate down to character positions and safe for the truncated preview.

Description

• Enable includeMatches in the launcher Fuse configuration and pass matches through the ranking pipeline so render code can access Fuse ranges (src/content/modules/launcher/main.ts).
• Add LauncherSearchResult type and update display_results to render per-character highlights using Fuse index ranges, inserting <mark> elements with class ultrabox-launcher-highlight for matched spans (src/content/modules/launcher/display_results.ts).
• Clip content match ranges to the 200-character preview to avoid out-of-bounds indices and adjust property access to the nested item structure where needed.
• Add CSS for .ultrabox-launcher-highlight to use a yellow background (#ffeb3b) and dark text (src/content/inject.css).

Testing

• Ran npm run build which completed successfully with webpack compiling the extension assets.
• Served the built dist output with python -m http.server successfully to validate runtime assets.
• Executed a Playwright check that opened http://127.0.0.1:4173/popup.html and produced a screenshot artifact, confirming the UI loads with the changes.

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Codex Task