Add FTP credentials management and UI enhancements

- Implement migration script to add ftp_username and ftp_password columns to nl43_config table.
- Create set_ftp_credentials.py script for updating FTP credentials in the database.
- Update requirements.txt to include aioftp for FTP functionality.
- Enhance index.html with FTP controls including enable, disable, check status, and list files features.
- Add JavaScript functions for handling FTP operations and displaying file lists.

set_ftp_credentials.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+"""
+Helper script to set FTP credentials for a device.
+Usage: python3 set_ftp_credentials.py <unit_id> <username> <password>
+"""
+
+import sys
+import sqlite3
+from pathlib import Path
+
+DB_PATH = Path(__file__).parent / "data" / "slmm.db"
+
+
+def set_credentials(unit_id: str, username: str, password: str):
+    """Set FTP credentials for a device."""
+
+    if not DB_PATH.exists():
+        print(f"Error: Database not found at {DB_PATH}")
+        sys.exit(1)
+
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+
+    try:
+        # Check if unit exists
+        cursor.execute("SELECT unit_id FROM nl43_config WHERE unit_id = ?", (unit_id,))
+        if not cursor.fetchone():
+            print(f"Error: Unit '{unit_id}' not found in database")
+            print("\nAvailable units:")
+            cursor.execute("SELECT unit_id FROM nl43_config")
+            for row in cursor.fetchall():
+                print(f"  - {row[0]}")
+            sys.exit(1)
+
+        # Update credentials
+        cursor.execute(
+            "UPDATE nl43_config SET ftp_username = ?, ftp_password = ? WHERE unit_id = ?",
+            (username, password, unit_id)
+        )
+        conn.commit()
+
+        print(f"✓ FTP credentials updated for unit '{unit_id}'")
+        print(f"  Username: {username}")
+        print(f"  Password: {'*' * len(password)}")
+
+    except Exception as e:
+        conn.rollback()
+        print(f"Error: {e}", file=sys.stderr)
+        sys.exit(1)
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    if len(sys.argv) != 4:
+        print("Usage: python3 set_ftp_credentials.py <unit_id> <username> <password>")
+        print("\nExample:")
+        print("  python3 set_ftp_credentials.py nl43-1 admin mypassword")
+        sys.exit(1)
+
+    unit_id = sys.argv[1]
+    username = sys.argv[2]
+    password = sys.argv[3]
+
+    set_credentials(unit_id, username, password)