docs: update all documentation to reflect current binder CLI

📚 Documentation Updates:
- Updated README.md with current binder commands
- Removed references to hello command (replaced with doctor)
- Updated CLI README.md to remove binder_legacy references
- Updated BINDER.md with current command set and shortcuts
- Removed check/check-tags from all documentation
- Updated doctor.py to only check for binder executable

🎯 Key Changes:
- All docs now reference current binder commands only
- Consistent command examples throughout documentation
- Updated shortcuts to match current CLI aliases
- Removed legacy command references
- Focus on build-centric workflow as intended

✅ Documentation Consistency:
- README.md: Updated quick start and development sections
- cli/README.md: Removed legacy references
- docs/BINDER.md: Updated command tables and examples
- All examples use current binder command structure

README.md

@@ -120,11 +120,12 @@ cd cs249r_book
 
 # Quick setup (recommended)
 ./binder setup      # Setup environment and dependencies
-./binder hello      # Welcome and overview
+./binder doctor     # Check system health
 
 # Fast development workflow
 ./binder preview intro    # Fast chapter development
-./binder build html       # Build complete book
+./binder build intro      # Build specific chapter
+./binder build            # Build complete book (HTML)
 ./binder help            # See all commands
 ```
 
@@ -164,24 +165,25 @@ The **Book Binder** is our lightning-fast development CLI for streamlined buildi
 ./binder preview intro,ml_systems     # Build and preview multiple chapters
 
 # Complete book building
-./binder build html                   # Build complete website
-./binder build pdf                    # Build complete PDF
-./binder build epub                   # Build complete EPUB
+./binder build                        # Build complete website (HTML)
+./binder pdf                          # Build complete PDF
+./binder epub                         # Build complete EPUB
 
 # Management
-./binder clean                    # Clean artifacts
-./binder status                   # Show current status
-./binder help                     # Show all commands
+./binder clean                        # Clean artifacts
+./binder status                       # Show current status
+./binder doctor                       # Run health check
+./binder help                         # Show all commands
 ```
 
 ### Development Commands
 ```bash
 # Book Binder CLI (Recommended)
 ./binder setup            # First-time setup
-./binder build html       # Build complete HTML book
-./binder build pdf        # Build complete PDF book  
+./binder build            # Build complete HTML book
+./binder pdf              # Build complete PDF book  
+./binder epub             # Build complete EPUB book
 ./binder preview intro    # Preview chapter development
-./binder publish          # Publish to production
 
 # Traditional setup (if needed)
 python3 -m venv .venv
@@ -261,12 +263,12 @@ MLSysBook/
 
 ### Getting Started
 ```bash
-# Welcome and overview
-./binder hello
-
 # First time setup
 ./binder setup
 
+# Check system health
+./binder doctor
+
 # Quick preview
 ./binder preview intro
 ```

cli/README.md

@@ -76,8 +76,7 @@ The modular CLI has replaced the original binder and is available as `./binder`
 
 The modular CLI has successfully replaced the original monolithic binder script:
 
-- **`./binder`** - New modular CLI (4000+ lines → organized modules)
-- **`./binder_legacy`** - Original monolithic script (backup)
+- **`./binder`** - Modular CLI (4000+ lines → organized modules)
 
 All functionality has been preserved and enhanced:
 - All existing commands work the same way

cli/commands/doctor.py

@@ -365,7 +365,6 @@ class DoctorCommand:
         """Check file permissions for key files."""
         key_files = [
             ("binder", self.config_manager.root_dir / "binder"),
-            ("binder_legacy", self.config_manager.root_dir / "binder_legacy"),
         ]
         
         for name, file_path in key_files:

docs/BINDER.md

@@ -74,12 +74,12 @@ Intuitive commands that work on both individual chapters and the entire book.
 | Command | Description | Example |
 |---------|-------------|---------|
 | `setup` | Configure environment | `./binder setup` |
-| `hello` | Welcome and overview | `./binder hello` |
 | `clean` | Clean configs & artifacts | `./binder clean` |
-| `check` | Check for build artifacts | `./binder check` |
 | `switch <format>` | Switch active config | `./binder switch pdf` |
 | `status` | Show current status | `./binder status` |
 | `list` | List available chapters | `./binder list` |
+| `doctor` | Run comprehensive health check | `./binder doctor` |
+| `about` | Show project information | `./binder about` |
 | `help` | Show help information | `./binder help` |
 
 ### 🚀 Shortcuts
@@ -91,14 +91,10 @@ All commands have convenient shortcuts:
 | `b` | `build` |
 | `p` | `preview` |
 | `pdf` | `pdf` |
-| `c` | `clean` |
-| `ch` | `check` |
-| `s` | `switch` |
-| `st` | `status` |
+| `epub` | `epub` |
 | `l` | `list` |
-| `he` | `hello` |
-| `se` | `setup` |
-| `pu` | `publish` |
+| `s` | `status` |
+| `d` | `doctor` |
 | `h` | `help` |
 
 ## Chapter Names
@@ -276,12 +272,12 @@ Use `./binder switch <format>` to change the active configuration symlink.
 # Clean up any build artifacts
 ./binder clean
 
-# Verify no artifacts remain
-./binder check
+# Run health check
+./binder doctor
 
 # Build full book to ensure everything works
-./binder build * html
-./binder build * pdf
+./binder build
+./binder pdf
 ```
 
 ## Troubleshooting
@@ -295,7 +291,7 @@ Use `./binder switch <format>` to change the active configuration symlink.
 
 **"Build artifacts detected"**
 - Run `./binder clean` to remove temporary files
-- Use `./binder check` to verify cleanup
+- Use `./binder doctor` to verify system health
 
 **"Config not clean"** 
 - The binder detected a previous fast build configuration