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/models/webhook.py

@@ -0,0 +1,63 @@
+"""Webhook model for external integrations."""
+
+import uuid
+from sqlalchemy import Column, String, Boolean, DateTime, Text, Integer, ForeignKey
+from sqlalchemy.sql import func
+
+from app.db.base import Base
+
+
+class Webhook(Base):
+    """Webhook configuration model."""
+
+    __tablename__ = "webhooks"
+
+    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    name = Column(String(100), nullable=False)
+    url = Column(String(500), nullable=False)
+    secret = Column(String(64), nullable=True)  # For signature verification
+
+    # Events to trigger on (JSON array stored as text)
+    events = Column(Text, nullable=False, default='["*"]')  # ["user.created", "user.updated", etc.]
+
+    # Configuration
+    is_active = Column(Boolean, default=True, nullable=False)
+    retry_count = Column(Integer, default=3, nullable=False)
+    timeout_seconds = Column(Integer, default=30, nullable=False)
+
+    # Metadata
+    created_by = Column(String(36), ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
+    created_at = Column(DateTime, server_default=func.now(), nullable=False)
+    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now(), nullable=False)
+
+    # Statistics
+    last_triggered_at = Column(DateTime, nullable=True)
+    success_count = Column(Integer, default=0, nullable=False)
+    failure_count = Column(Integer, default=0, nullable=False)
+
+
+class WebhookDelivery(Base):
+    """Webhook delivery log model."""
+
+    __tablename__ = "webhook_deliveries"
+
+    id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    webhook_id = Column(String(36), ForeignKey("webhooks.id", ondelete="CASCADE"), nullable=False)
+
+    # Event details
+    event_type = Column(String(50), nullable=False)
+    payload = Column(Text, nullable=False)  # JSON payload
+
+    # Delivery status
+    status = Column(String(20), default="pending", nullable=False)  # pending, success, failed
+    status_code = Column(Integer, nullable=True)
+    response_body = Column(Text, nullable=True)
+    error_message = Column(Text, nullable=True)
+
+    # Retry tracking
+    attempt_count = Column(Integer, default=0, nullable=False)
+    next_retry_at = Column(DateTime, nullable=True)
+
+    # Timestamps
+    created_at = Column(DateTime, server_default=func.now(), nullable=False)
+    delivered_at = Column(DateTime, nullable=True)