🔗 Auto-register apps: Universal index discovery (#64)

* feat: Enhance CLI with improved list and smart remove commands

## ✨ New Features

### 🏠 Enhanced `leann list` command
- **Better UX**: Current project shown first with clear separation
- **Visual improvements**: Icons (🏠/📂), better formatting, size info
- **Smart guidance**: Context-aware usage examples and getting started tips

### 🛡️ Smart `leann remove` command
- **Safety first**: Always shows ALL matching indexes across projects
- **Intelligent handling**:
  - Single match: Clear location display with cross-project warnings
  - Multiple matches: Interactive selection with final confirmation
- **Prevents accidents**: No more deleting wrong indexes due to name conflicts
- **User-friendly**: 'c' to cancel, clear visual hierarchy, detailed info

### 🔧 Technical improvements
- **Clean logging**: Hide debug messages for better CLI experience
- **Comprehensive search**: Always scan all projects for transparency
- **Error handling**: Graceful handling of edge cases and user input

## 🎯 Impact
- **Safer**: Eliminates risk of accidental index deletion
- **Clearer**: Users always know what they're operating on
- **Smarter**: Automatic detection and handling of common scenarios

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: vscode ruff, and format

---------

Co-authored-by: Claude <noreply@anthropic.com>

README.md

@@ -542,8 +542,10 @@ Options:
 leann list
 
 # Lists all indexes across all projects with status indicators:
-# ✓ - Index is complete and ready to use
-# ✗ - Index is incomplete or corrupted
+# ✅ - Index is complete and ready to use
+# ❌ - Index is incomplete or corrupted
+# 📁 - CLI-created index (in .leann/indexes/)
+# 📄 - App-created index (*.leann.meta.json files)
 ```
 
 **Remove Command:**
@@ -557,6 +559,7 @@ Options:
 # - Shows all matching indexes across projects
 # - Requires confirmation for cross-project removal
 # - Interactive selection when multiple matches found
+# - Supports both CLI and app-created indexes
 ```
 
 </details>