fix: 'o' key should jump to VS Code terminal, not just open app

[aparente]

Current Behavior

Pressing 'o' on a VS Code session runs open -a 'Visual Studio Code' which just activates the app window, not the specific terminal.

Expected Behavior

Should focus the actual terminal pane where Claude Code is running.

Technical Details

• focusTerminal() in src/server.ts (lines 201-212) has basic VS Code handling
• Need to either:
  • Use VS Code CLI (code --goto) with terminal ID
  • Use AppleScript to focus specific terminal tab
  • Use VS Code extension API (longer term)

Acceptance Criteria

• Pressing 'o' on VS Code session focuses the terminal pane
• Works when multiple terminals are open