Enhance user profile management and Gravatar integration

- Added email field to user profile API and frontend components for better user identification.
- Implemented PATCH /map/api/me endpoint to update user email, enhancing user experience.
- Introduced useGravatarUrl composable for generating Gravatar URLs based on user email.
- Updated profile and layout components to display user avatars using Gravatar, improving visual consistency.
- Enhanced development documentation to guide testing of navbar and profile features.

docs/api.md

@@ -5,7 +5,7 @@ The API is available under the `/map/api/` prefix. Requests requiring authentica
 ## Authentication
 
 - **POST /map/api/login** — sign in. Body: `{"user":"...","pass":"..."}`. On success returns JSON with user data and sets a session cookie. On first run, bootstrap is available: logging in as `admin` with the password from `HNHMAP_BOOTSTRAP_PASSWORD` creates the first admin user. For users created via OAuth (no password), returns 401 with `{"error":"Use OAuth to sign in"}`.
-- **GET /map/api/me** — current user (by session). Response: `username`, `auths`, and optionally `tokens`, `prefix`.
+- **GET /map/api/me** — current user (by session). Response: `username`, `auths`, and optionally `tokens`, `prefix`, `email` (string, optional — for Gravatar and display).
 - **POST /map/api/logout** — sign out (invalidates the session).
 - **GET /map/api/setup** — check if initial setup is needed. Response: `{"setupRequired": true|false}`.
 
@@ -17,6 +17,7 @@ The API is available under the `/map/api/` prefix. Requests requiring authentica
 
 ## User account
 
+- **PATCH /map/api/me** — update current user. Body: `{"email": "..."}`. Used to set or change the user's email (for Gravatar and profile display). Requires a valid session.
 - **POST /map/api/me/tokens** — generate a new upload token (requires `upload` permission). Response: `{"tokens": ["...", ...]}`.
 - **POST /map/api/me/password** — change password. Body: `{"pass":"..."}`.