feat(auth): implement Phase 4 user profile and API key endpoints

Add user profile, preferences, and API key management endpoints:
- GET /auth/users/me - full user profile with roles and preferences
- GET/PATCH /auth/users/me/preferences - user preferences management
- GET/POST/DELETE /auth/users/me/api-keys - API key lifecycle

API keys use tak_ prefix, SHA-256 hashing, and are shown only once on creation.
Preferences support partial updates with JSON merge behavior.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/domains/auth/schemas.py

@@ -145,3 +145,67 @@ class GroupRoleAssignmentResponse(BaseSchema):
     group_id: uuid.UUID = Field(..., description="Group ID")
     group_name: str = Field(..., description="Group name")
     roles: list[str] = Field(..., description="Currently assigned role names")
+
+
+# =============================================================================
+# User Profile (Phase 4)
+# =============================================================================
+
+class UserProfileResponse(BaseSchema):
+    """Response from GET /users/me - full user profile"""
+
+    user: UserSchema = Field(..., description="User profile")
+    roles: list[RoleSchema] = Field(..., description="User's permission roles")
+    preferences: UserPreferencesSchema = Field(..., description="User preferences")
+
+
+class PreferencesUpdateRequest(BaseSchema):
+    """Request for PATCH /users/me/preferences"""
+
+    theme: Optional[str] = Field(None, description="Theme preference: system, light, dark")
+    default_room: Optional[str] = Field(None, description="Default room for housekeeping")
+    preferences_json: Optional[dict] = Field(None, description="Extended preferences (merged)")
+
+
+# =============================================================================
+# API Keys (Phase 4)
+# =============================================================================
+
+class ApiKeyCreateRequest(BaseSchema):
+    """Request for POST /users/me/api-keys"""
+
+    name: str = Field(..., min_length=1, max_length=100, description="Human-readable key name")
+    scopes: Optional[list[str]] = Field(None, description="Optional scope restriction (role names)")
+    expires_in_days: Optional[int] = Field(None, ge=1, le=365, description="Days until expiration (optional)")
+
+
+class ApiKeyCreateResponse(BaseSchema):
+    """Response from POST /users/me/api-keys - includes the key (shown only once)"""
+
+    id: uuid.UUID = Field(..., description="API key ID")
+    name: str = Field(..., description="Key name")
+    key: str = Field(..., description="The API key (shown only once!)")
+    key_prefix: str = Field(..., description="Key prefix for identification")
+    scopes: Optional[list[str]] = Field(None, description="Scope restriction")
+    expires_at: Optional[datetime] = Field(None, description="Expiration timestamp")
+    created_at: datetime = Field(..., description="Creation timestamp")
+
+
+class ApiKeySchema(BaseSchema):
+    """API key information (without the actual key)"""
+
+    id: uuid.UUID = Field(..., description="API key ID")
+    name: str = Field(..., description="Key name")
+    key_prefix: str = Field(..., description="Key prefix for identification (e.g., 'tak_abc1')")
+    scopes: Optional[list[str]] = Field(None, description="Scope restriction")
+    expires_at: Optional[datetime] = Field(None, description="Expiration timestamp")
+    last_used_at: Optional[datetime] = Field(None, description="Last usage timestamp")
+    created_at: datetime = Field(..., description="Creation timestamp")
+    is_expired: bool = Field(..., description="Whether the key has expired")
+
+
+class ApiKeysListResponse(BaseSchema):
+    """Response from GET /users/me/api-keys"""
+
+    items: list[ApiKeySchema] = Field(..., description="List of API keys")
+    total: int = Field(..., description="Total count of keys")