File Tree Tab Test

# 🧪 File Tree Tab Test Results

## Test Instructions:

1. Open the Claude MPM Dashboard at http://localhost:8765
2. Click on the "File Tree" tab
3. Verify what content is displayed

## Expected Behavior:

✅ File Tree tab should show D3.js tree visualization
✅ Tree should show at least a session root node
✅ No event items should be visible
✅ Control buttons: Expand All, Collapse All, Reset Zoom
✅ Legend showing file/class/function/method indicators

## Fixed Issues:

🔧 EventViewer now respects container ID passed to constructor
🔧 UIStateManager cleans up leaked event items from non-event tabs
🔧 CodeViewer aggressively removes foreign content from its container
🔧 Added tab activity checks to prevent rendering in inactive tabs

## Console Commands for Testing:

    // Check if File Tree tab is active
    document.getElementById('claude-tree-tab').classList.contains('active')

    // Check File Tree container content
    document.getElementById('claude-tree-container').children.length

    // Force render the tree
    window.CodeViewer.show()

    // Check for leaked event items
    document.querySelectorAll('#claude-tree-container .event-item').length

## Files Modified:

- `/src/claude_mpm/dashboard/static/js/components/event-viewer.js`
- `/src/claude_mpm/dashboard/static/js/components/ui-state-manager.js`
- `/src/claude_mpm/dashboard/static/js/components/code-viewer.js`