fix: Fix ImportError in alert_processor alerts.py by using DatabaseManager pattern

The alert_processor service was crashing with:
ImportError: cannot import name 'get_db' from 'shared.database.base'

Root cause: alerts.py was using Depends(get_db) pattern which doesn't exist
in shared.database.base.

Fix: Refactored alerts.py to follow the same pattern as analytics.py:
- Removed Depends(get_db) dependency injection
- Each endpoint now creates a DatabaseManager instance
- Uses db_manager.get_session() context manager for database access

This matches the alert_processor service's existing architecture in analytics.py.

services/alert_processor/app/api/alerts.py

@@ -3,15 +3,13 @@
 Alerts API endpoints for dashboard and alert management
 """
 
-from fastapi import APIRouter, Depends, HTTPException, Query, Path
-from sqlalchemy.ext.asyncio import AsyncSession
+from fastapi import APIRouter, HTTPException, Query, Path
 from typing import List, Optional
 from pydantic import BaseModel, Field
 from uuid import UUID
 from datetime import datetime
 import structlog
 
-from shared.database.base import get_db
 from app.repositories.alerts_repository import AlertsRepository
 from app.models.alerts import AlertSeverity, AlertStatus
 
@@ -76,8 +74,7 @@ class AlertsListResponse(BaseModel):
     description="Get summary of alerts by severity and status for dashboard health indicator"
 )
 async def get_alerts_summary(
-    tenant_id: UUID = Path(..., description="Tenant ID"),
-    db: AsyncSession = Depends(get_db)
+    tenant_id: UUID = Path(..., description="Tenant ID")
 ) -> AlertsSummaryResponse:
     """
     Get alerts summary for dashboard
@@ -85,10 +82,17 @@ async def get_alerts_summary(
     Returns counts of alerts grouped by severity and status.
     Critical count maps to URGENT severity for dashboard compatibility.
     """
+    from app.config import AlertProcessorConfig
+    from shared.database.base import create_database_manager
+
     try:
-        repo = AlertsRepository(db)
-        summary = await repo.get_alerts_summary(tenant_id)
-        return AlertsSummaryResponse(**summary)
+        config = AlertProcessorConfig()
+        db_manager = create_database_manager(config.DATABASE_URL, "alert-processor")
+
+        async with db_manager.get_session() as session:
+            repo = AlertsRepository(session)
+            summary = await repo.get_alerts_summary(tenant_id)
+            return AlertsSummaryResponse(**summary)
 
     except Exception as e:
         logger.error("Error getting alerts summary", error=str(e), tenant_id=str(tenant_id))
@@ -107,8 +111,7 @@ async def get_alerts(
     status: Optional[str] = Query(None, description="Filter by status: active, resolved, acknowledged, ignored"),
     resolved: Optional[bool] = Query(None, description="Filter by resolved status: true=resolved only, false=unresolved only"),
     limit: int = Query(100, ge=1, le=1000, description="Maximum number of results"),
-    offset: int = Query(0, ge=0, description="Pagination offset"),
-    db: AsyncSession = Depends(get_db)
+    offset: int = Query(0, ge=0, description="Pagination offset")
 ) -> AlertsListResponse:
     """
     Get filtered list of alerts
@@ -119,6 +122,9 @@ async def get_alerts(
     - resolved: boolean filter for resolved status
     - pagination: limit and offset
     """
+    from app.config import AlertProcessorConfig
+    from shared.database.base import create_database_manager
+
     try:
         # Validate severity enum
         if severity and severity not in [s.value for s in AlertSeverity]:
@@ -134,43 +140,47 @@ async def get_alerts(
                 detail=f"Invalid status. Must be one of: {[s.value for s in AlertStatus]}"
             )
 
-        repo = AlertsRepository(db)
-        alerts = await repo.get_alerts(
-            tenant_id=tenant_id,
-            severity=severity,
-            status=status,
-            resolved=resolved,
-            limit=limit,
-            offset=offset
-        )
+        config = AlertProcessorConfig()
+        db_manager = create_database_manager(config.DATABASE_URL, "alert-processor")
 
-        # Convert to response models
-        alert_responses = [
-            AlertResponse(
-                id=str(alert.id),
-                tenant_id=str(alert.tenant_id),
-                item_type=alert.item_type,
-                alert_type=alert.alert_type,
-                severity=alert.severity,
-                status=alert.status,
-                service=alert.service,
-                title=alert.title,
-                message=alert.message,
-                actions=alert.actions,
-                alert_metadata=alert.alert_metadata,
-                created_at=alert.created_at,
-                updated_at=alert.updated_at,
-                resolved_at=alert.resolved_at
+        async with db_manager.get_session() as session:
+            repo = AlertsRepository(session)
+            alerts = await repo.get_alerts(
+                tenant_id=tenant_id,
+                severity=severity,
+                status=status,
+                resolved=resolved,
+                limit=limit,
+                offset=offset
             )
-            for alert in alerts
-        ]
 
-        return AlertsListResponse(
-            alerts=alert_responses,
-            total=len(alert_responses),  # In a real implementation, you'd query the total count separately
-            limit=limit,
-            offset=offset
-        )
+            # Convert to response models
+            alert_responses = [
+                AlertResponse(
+                    id=str(alert.id),
+                    tenant_id=str(alert.tenant_id),
+                    item_type=alert.item_type,
+                    alert_type=alert.alert_type,
+                    severity=alert.severity,
+                    status=alert.status,
+                    service=alert.service,
+                    title=alert.title,
+                    message=alert.message,
+                    actions=alert.actions,
+                    alert_metadata=alert.alert_metadata,
+                    created_at=alert.created_at,
+                    updated_at=alert.updated_at,
+                    resolved_at=alert.resolved_at
+                )
+                for alert in alerts
+            ]
+
+            return AlertsListResponse(
+                alerts=alert_responses,
+                total=len(alert_responses),  # In a real implementation, you'd query the total count separately
+                limit=limit,
+                offset=offset
+            )
 
     except HTTPException:
         raise
@@ -187,33 +197,39 @@ async def get_alerts(
 )
 async def get_alert(
     tenant_id: UUID = Path(..., description="Tenant ID"),
-    alert_id: UUID = Path(..., description="Alert ID"),
-    db: AsyncSession = Depends(get_db)
+    alert_id: UUID = Path(..., description="Alert ID")
 ) -> AlertResponse:
     """Get a specific alert by ID"""
+    from app.config import AlertProcessorConfig
+    from shared.database.base import create_database_manager
+
     try:
-        repo = AlertsRepository(db)
-        alert = await repo.get_alert_by_id(tenant_id, alert_id)
+        config = AlertProcessorConfig()
+        db_manager = create_database_manager(config.DATABASE_URL, "alert-processor")
 
-        if not alert:
-            raise HTTPException(status_code=404, detail="Alert not found")
+        async with db_manager.get_session() as session:
+            repo = AlertsRepository(session)
+            alert = await repo.get_alert_by_id(tenant_id, alert_id)
 
-        return AlertResponse(
-            id=str(alert.id),
-            tenant_id=str(alert.tenant_id),
-            item_type=alert.item_type,
-            alert_type=alert.alert_type,
-            severity=alert.severity,
-            status=alert.status,
-            service=alert.service,
-            title=alert.title,
-            message=alert.message,
-            actions=alert.actions,
-            alert_metadata=alert.alert_metadata,
-            created_at=alert.created_at,
-            updated_at=alert.updated_at,
-            resolved_at=alert.resolved_at
-        )
+            if not alert:
+                raise HTTPException(status_code=404, detail="Alert not found")
+
+            return AlertResponse(
+                id=str(alert.id),
+                tenant_id=str(alert.tenant_id),
+                item_type=alert.item_type,
+                alert_type=alert.alert_type,
+                severity=alert.severity,
+                status=alert.status,
+                service=alert.service,
+                title=alert.title,
+                message=alert.message,
+                actions=alert.actions,
+                alert_metadata=alert.alert_metadata,
+                created_at=alert.created_at,
+                updated_at=alert.updated_at,
+                resolved_at=alert.resolved_at
+            )
 
     except HTTPException:
         raise