Update current user profile

Update the currently authenticated user's profile information.

Allows users to modify their personal information including first and last name. Only the fields provided in the request body will be updated. Omitted fields remain unchanged. The user is automatically identified from their authentication credentials.

Context: - Only first_name and last_name can be updated via this endpoint - Password field in request body is reserved for future use (not implemented) - Email, role, status, and organization cannot be changed by users - Updates are immediate and reflected in database upon success - Full user profile returned in response with updated values

Behavior: 1. Extracts user_id from authenticated user context 2. Validates request body fields (min/max length constraints) 3. Queries database to verify user exists 4. Updates only first_name and last_name if provided 5. Persists changes to database with updated_at timestamp 6. Returns complete updated user profile

Use Cases: - User wants to correct misspelled name - User prefers different name display (nickname vs full name) - User changes last name after marriage or legal name change - Profile updates during onboarding or account setup - Internationalization of name display

Field Update Rules: - first_name: 1-100 characters if provided, unchanged if null - last_name: 1-100 characters if provided, unchanged if null - password: Not currently implemented, reserved for future use - All other fields (email, role, status): Use admin endpoints to modify

Related Endpoints: - GET /profile/me - Retrieve current user profile - PUT /admin/users/{user_id} - Admin endpoint to update any user - POST /auth/change-password - Change password (separate auth flow)