[FEATURE] Chat tab in-conversation search (Cmd+F) lacking next/previous keyboard navigation.

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

This is specific to the Claude Desktop app → Chat tab, not the CLI/TUI. The Cmd+F search in the Chat tab requires mouse clicks to navigate between results — there is no keyboard shortcut for next/previous match.

Example: searching "comm" returns 1/19. Currently at result 1 (the oldest/first occurrence, at the top of the conversation). To reach result 19 (the newest occurrence), I must click the ↓ arrow 18 times with the mouse. There is no keyboard shortcut to trigger the existing ↑/↓ navigation buttons at all.

### Proposed Solution

If we can have a keyboard shortcut something like Cmd+G/Cmd+Shift+G for next/previous result (standard Mac pattern) that would be productive.

### Alternative Solutions

Currently clicking the forward/backward arrows in the Cmd+F search bar with the mouse each time. No keyboard workaround exists for next/previous result in the Chat tab. claude-history (third-party TUI tool) solves this for Claude Code sessions but not for Chat tab conversations.


### Priority

Medium - Would be very helpful

### Feature Category

Other

### Use Case Example

Claude Desktop app → Chat tab → Cmd+F in-conversation search

### Additional Context

Standard Mac convention: Cmd+G / Cmd+Shift+G for next/previous result is used by Safari, Preview, Finder, Xcode, and virtually every macOS app. Enter / Shift+Enter is used by VS Code and browser DevTools. Either convention would be acceptable.