Add user authentication system with API key management (#50)

- Add User, Session, AuthSettings models with bcrypt password hashing
- Add auth endpoints: login, logout, change-password, me
- Add API key CRUD: create (orch_xxx format), list, revoke
- Add admin user management: list, create, update, reset-password
- Create default admin user on startup (admin/admin)
- Add frontend: Login page, API Keys page, Admin Users page
- Add AuthContext for session state management
- Add user menu to Layout header with login/logout/settings
- Add 15 integration tests for auth system
- Add migration 006_auth_tables.sql

backend/app/schemas.py

@@ -686,3 +686,93 @@ class StatsReportResponse(BaseModel):
     format: str  # "json", "csv", "markdown"
     generated_at: datetime
     content: str  # The report content
+
+
+# Authentication schemas
+class LoginRequest(BaseModel):
+    """Login request with username and password"""
+    username: str
+    password: str
+
+
+class LoginResponse(BaseModel):
+    """Login response with user info"""
+    id: UUID
+    username: str
+    email: Optional[str]
+    is_admin: bool
+    must_change_password: bool
+
+
+class ChangePasswordRequest(BaseModel):
+    """Change password request"""
+    current_password: str
+    new_password: str
+
+
+class UserResponse(BaseModel):
+    """User information response"""
+    id: UUID
+    username: str
+    email: Optional[str]
+    is_admin: bool
+    is_active: bool
+    must_change_password: bool
+    created_at: datetime
+    last_login: Optional[datetime]
+
+    class Config:
+        from_attributes = True
+
+
+class UserCreate(BaseModel):
+    """Create user request (admin only)"""
+    username: str
+    password: str
+    email: Optional[str] = None
+    is_admin: bool = False
+
+
+class UserUpdate(BaseModel):
+    """Update user request (admin only)"""
+    email: Optional[str] = None
+    is_admin: Optional[bool] = None
+    is_active: Optional[bool] = None
+
+
+class ResetPasswordRequest(BaseModel):
+    """Reset password request (admin only)"""
+    new_password: str
+
+
+class APIKeyCreate(BaseModel):
+    """Create API key request"""
+    name: str
+    description: Optional[str] = None
+    scopes: Optional[List[str]] = None
+
+
+class APIKeyResponse(BaseModel):
+    """API key response (without the secret key)"""
+    id: UUID
+    name: str
+    description: Optional[str]
+    scopes: Optional[List[str]]
+    created_at: datetime
+    expires_at: Optional[datetime]
+    last_used: Optional[datetime]
+
+    class Config:
+        from_attributes = True
+
+
+class APIKeyCreateResponse(BaseModel):
+    """API key creation response (includes the secret key - only shown once)"""
+    id: UUID
+    name: str
+    description: Optional[str]
+    scopes: Optional[List[str]]
+    key: str  # The actual API key - only returned on creation
+    created_at: datetime
+    expires_at: Optional[datetime]
+