## Why

The platform has authentication but users cannot view or edit their own profile information. Implementing profile management is essential for personalization and account management.

## What Changes

- Add authenticated user profile API endpoints (read, update, avatar upload).
- Add a frontend profile page with editable form and avatar upload.
- Validate avatar file type and size on upload.
- Store avatars locally and update the user's avatar_url.

## Capabilities

### New Capabilities
- `user-profile-management`: Users can view and edit their profile (name, email) and upload an avatar.

### Modified Capabilities
- `auth-oauth`: Extend /auth/me or add dedicated /users/me endpoint for richer profile data.

## Impact

- Backend changes in `apps/api/src/api/` (new users router) and storage for avatars.
- Frontend changes in `apps/web/src/` (new profile page, API methods, routing).
- No schema migrations required (avatar_url already exists on User model).