Add admin reset-password command

Features:
- Add admin reset-password command to reset user passwords
- Support SQLite, PostgreSQL, and MySQL databases
- Use scrypt hashing compatible with CodiMD
- Update README with reset-password usage examples

cli_anything/codimd/codimd_cli.py

@@ -708,6 +708,76 @@ def admin_user_notes(user_id, db_path):
                 click.echo(f"  {note_id} | {title[:50]} | [{permission}]")
 
 
+@admin.command("reset-password")
+@click.option("--db-type", type=click.Choice(["sqlite", "postgresql", "mysql"]), default="sqlite", help="Database type")
+@click.option("--db-path", type=Path, help="SQLite database path")
+@click.option("--db-host", help="Database host (for PostgreSQL/MySQL)")
+@click.option("--db-name", help="Database name (for PostgreSQL/MySQL)")
+@click.option("--db-user", help="Database user (for PostgreSQL/MySQL)")
+@click.option("--db-password", help="Database password (for PostgreSQL/MySQL)")
+@click.option("--db-port", type=int, default=5432, help="Database port")
+@click.option("--email", help="User email to reset password for")
+@click.option("--user-id", help="User ID to reset password for")
+@click.option("--password", help="New password (will prompt if not provided)")
+@click.confirmation_option(prompt="Are you sure you want to reset this user's password?")
+@handle_error
+def admin_reset_password(db_type, db_path, db_host, db_name, db_user, db_password, db_port, email, user_id, password):
+    """Reset a user's password."""
+    from cli_anything.codimd.core import CodiMDDatabase
+
+    if not email and not user_id:
+        raise ValueError("Either --email or --user-id must be specified")
+
+    if not password:
+        password = click.prompt("New password", hide_input=True, confirmation_prompt=True)
+
+    if db_type == "sqlite":
+        if not db_path:
+            # Try default paths
+            default_paths = [
+                "./codimd/db.sqlite",
+                "./db.sqlite",
+                "/var/lib/codimd/db.sqlite"
+            ]
+            for path in default_paths:
+                if Path(path).exists():
+                    db_path = path
+                    break
+            if not db_path:
+                raise ValueError("SQLite database path not found. Use --db-path")
+
+        if user_id:
+            CodiMDDatabase.reset_password_sqlite_by_id(str(db_path), user_id, password)
+            click.echo(f"Password reset for user ID: {user_id}")
+        else:
+            CodiMDDatabase.reset_password_sqlite(str(db_path), email, password)
+            click.echo(f"Password reset for: {email}")
+
+    elif db_type == "postgresql":
+        if not all([db_host, db_name, db_user]):
+            raise ValueError("--db-host, --db-name, and --db-user are required for PostgreSQL")
+        if not db_password:
+            db_password = click.prompt("Database password", hide_input=True)
+
+        CodiMDDatabase.reset_password_postgresql(
+            db_host, db_name, db_user, db_password, db_port, email, password
+        )
+        click.echo(f"Password reset for: {email}")
+
+    elif db_type == "mysql":
+        if not all([db_host, db_name, db_user]):
+            raise ValueError("--db-host, --db-name, and --db-user are required for MySQL")
+        if not db_password:
+            db_password = click.prompt("Database password", hide_input=True)
+
+        CodiMDDatabase.reset_password_mysql(
+            db_host, db_name, db_user, db_password, db_port, email, password
+        )
+        click.echo(f"Password reset for: {email}")
+
+    click.echo("✓ Password has been updated. The user can now log in with the new password.")
+
+
 # REPL mode
 @cli.command("repl")
 @handle_error