Add unified search interface (Fuzzy Finder)

[lambdalisue]

Summary

Implement a unified search interface (Fuzzy Finder) that integrates the existing in-file search with a new directory-wide search.

Proposed Behavior

Fuzzy Finder Panel

• Opens as an overlay at the top-center of the window (Raycast/VS Code command palette style)
• Cmd+F → Opens with "In current file" mode selected
• Cmd+Shift+F → Opens with "In current directory" mode selected
• Mode switch component to toggle between the two modes
• Real-time fuzzy matching results list below the input field (scored and ranked)

In current file mode

• Fuzzy search within current file content
• Highlights matches in the content viewer
• Results shown in ranked list below the input

In current directory mode

• Fuzzy search across all files under the sidebar root directory
• Respects .gitignore
• Results show file path + line number + match context
• Selecting a result opens the file and scrolls to the matched line

Escape behavior

• Closes the Fuzzy Finder panel
• Search results are preserved and viewable in the right sidebar Search tab

Right sidebar Search tab

• Shows global results (not limited to current tab)
• Includes results from both "In current file" and "In current directory" modes
• Clicking a result opens the target file and scrolls to the matched line

Pin

• Pin functionality available from the Fuzzy Finder (same as current behavior)
• Pinned searches persist across sessions

[lambdalisue]

I tried creating a unified interface as an experiment, but it doesn’t seem very usable. It is probably better to think about this not as a single unified interface, but as three separate features:

1. In-file word search (already provided).
2. Grep search within a directory (this is the most difficult part: when converting Markdown to HTML, the highlight positions get misaligned. Frontmatter in particular is basically hopeless).
3. Fuzzy file (path) finder within a directory or across the OS (this should not be too difficult by leveraging tools like mdfind or nucleo).