Me

Get current user information. Validates authentication and returns user details.

**Authentication Required:**
One of the following authentication methods must be used:
- Bearer token in `Authorization` header: `Authorization: Bearer <access_token>`
- Session token in `Authorization` header: `Authorization: Session <session_token>`
- API Key in `Authorization` header: `Authorization: APIKey <api_key>`

**Headers:**
- `Authorization`: Authentication token (required)
- `X-Client-Type`: Client type for logging (optional, default: papr_plugin)

**Response:**
- `user_id`: Internal user ID
- `sessionToken`: Session token for API access (if available)
- `imageUrl`: User profile image URL (if available)
- `displayName`: User display name (if available)
- `email`: User email address (if available)
- `message`: Authentication status message

**Example:**
```
GET /me
Authorization: Bearer eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
X-Client-Type: papr_plugin
```