deprecate: mark CLI as deprecated, recommend web interface

- Add DEPRECATED notice to minimal_app.py docstring
- Add deprecation warning at startup
- Update README.md to mark CLI as deprecated
- Remove CLI from Quick Start, promote web interface
- Note limited functionality in CLI description

The CLI (minimal_app.py) is now officially deprecated. Users should
use the full-featured web interface (app.py) instead.

minimal_app.py

@@ -1,7 +1,23 @@
 #!/usr/bin/env python3
 """
-Minimal Tablet Lending and Return Management System
-Using only built-in Python modules
+DEPRECATED - Tablet Lending and Return Management System (CLI)
+
+This CLI version is DEPRECATED. Please use the web interface instead.
+
+The web interface (app.py) provides full functionality including:
+- Complete user management (name, email, phone, identification)
+- Full tablet management with notes field
+- User loans view with search
+- Edit functionality for non-loanable devices
+- Project management
+- Responsive mobile interface
+
+To run the web interface:
+    python3 app.py
+
+Then open http://localhost:5000 in your browser.
+
+This CLI will be removed in a future version.
 """
 
 import sqlite3
@@ -273,10 +289,17 @@ def delete_non_loanable_device(device_id):
 
 def main():
     """Main menu"""
+    print("=" * 70)
+    print("DEPRECATION WARNING: This CLI is deprecated!")
+    print("Please use the web interface instead: python3 app.py")
+    print("=" * 70)
+    print()
+    
     init_db()
     
-    print("=== Tablet Lending and Return Management System ===")
+    print("=== Tablet Lending and Return Management System (DEPRECATED) ===")
     print("Using SQLite database: tablets.db")
+    print("NOTE: This CLI has limited functionality. Use web interface for full features.")
     
     while True:
         print("\nMenu:")