[Bug] VS Code Extension: Input Text Area Selection and Clearing Broken on macOS

Bug Description
Problem: Unable to clear text in Claude's input text area in VS Code extension on macOS

Current Behavior:

• Standard text selection shortcuts don't work properly:
• Cmd+A selects the entire terminal instead of just the text area content
• Triple-click only selects a single line
• Click and drag selection doesn't work as expected
• No clear button or X button visible in the UI
• Common clear shortcuts (Cmd+K, Escape) don't work

Additional Problem:

• Claude sometimes automatically duplicates previous messages multiple times in the text area
• When this happens, there's no easy way to clear the duplicated content

Impact:

• Makes it difficult to manage long or corrupted input
• Particularly problematic when Claude auto-inserts duplicated content
• Forces users to close/reopen the panel as a workaround

Environment:

• VS Code on macOS
• Claude Code extension

Expected Behavior:

• Cmd+A should select only text area content when focused
• Should have a clear button or keyboard shortcut (like Cmd+K) to clear input
• Prevent automatic duplication of previous messages

Suggested Solutions:

1. Add a dedicated clear button in the UI
2. Implement Cmd+K shortcut for clearing input
3. Fix Cmd+A to work within text area context only
4. Fix the bug causing message duplication

Environment Info

• Platform: darwin
• Terminal: vscode
• Version: 1.0.123
• Feedback ID: daef1254-7728-403d-a7e9-a4e1730c28bd