Add comprehensive backend features and mobile UI improvements

Backend:
- Add 2FA authentication with TOTP support
- Add API keys management system
- Add audit logging for security events
- Add file upload/management system
- Add notifications system with preferences
- Add session management
- Add webhooks integration
- Add analytics endpoints
- Add export functionality
- Add password policy enforcement
- Add new database migrations for core tables

Frontend:
- Add module position system (top/bottom sidebar sections)
- Add search and notifications module configuration tabs
- Add mobile logo replacing hamburger menu
- Center page title absolutely when no tabs present
- Align sidebar footer toggles with navigation items
- Add lighter icon color in dark theme for mobile
- Add API keys management page
- Add notifications page with context
- Add admin analytics and audit logs pages

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

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

backend/app/schemas/auth.py

@@ -11,6 +11,15 @@ class Token(BaseModel):
     token_type: str = "bearer"
 
 
+class TokenWith2FA(BaseModel):
+    """JWT token response with 2FA requirement indicator."""
+
+    access_token: Optional[str] = None
+    token_type: str = "bearer"
+    requires_2fa: bool = False
+    temp_token: Optional[str] = None  # Temporary token for 2FA verification
+
+
 class TokenData(BaseModel):
     """Token payload data schema."""
 
@@ -22,6 +31,14 @@ class LoginRequest(BaseModel):
 
     username: str = Field(..., min_length=3, max_length=100)
     password: str = Field(..., min_length=1)
+    totp_code: Optional[str] = Field(None, min_length=6, max_length=8)  # 6 digits or 8-char backup code
+
+
+class Verify2FARequest(BaseModel):
+    """2FA verification request schema."""
+
+    temp_token: str
+    code: str = Field(..., min_length=6, max_length=8)
 
 
 class RegisterRequest(BaseModel):