feat: Replace hardcoded dashboard insights with real data from services

MAJOR FIX: Dashboard now shows actual business data instead of mock values

The Bug:
--------
Dashboard insights were displaying hardcoded values:
- Savings: Always showed "€124 this week"
- Deliveries: Always showed "0 arriving today"
- Not reflecting actual business activity

Root Cause:
-----------
Line 468-472 in dashboard.py had hardcoded mock savings data:
```python
savings_data = {
    "weekly_savings": 124,
    "trend_percentage": 12
}
```

Deliveries data wasn't being fetched from any service.

The Fix:
--------
1. **Real Savings Calculation:**
   - Fetches last 7 days of purchase orders
   - Sums up actual savings from price optimization
   - Uses po.optimization_data.savings field
   - Calculates: weekly_savings from PO optimization savings
   - Result: Shows €X based on actual cost optimizations

2. **Real Deliveries Data:**
   - Fetches pending purchase orders from procurement service
   - Counts POs with expected_delivery_date == today
   - Result: Shows actual number of deliveries arriving today

3. **Data Flow:**
   ```
   procurement_client.get_pending_purchase_orders()
   → Filter by created_at (last 7 days) for savings
   → Filter by expected_delivery_date (today) for deliveries
   → Calculate totals
   → Pass to dashboard_service.calculate_insights()
   ```

Benefits:
---------
✅ Savings widget shows real optimization results
✅ Deliveries widget shows actual incoming deliveries
✅ Inventory widget already uses real stock data
✅ Waste widget already uses real sustainability data
✅ Dashboard reflects actual business activity

Note: Trend percentage for savings still defaults to 12% as it
requires historical comparison data (future enhancement).

services/orchestrator/app/api/dashboard.py

@@ -465,11 +465,70 @@ async def get_insights(
         except Exception as e:
             logger.warning(f"Failed to fetch inventory data: {e}")
 
-        # Savings data (mock for now)
+        # Deliveries data from procurement
+        delivery_data = {}
+        try:
+            # Get recent POs with pending deliveries
+            pos_result = await procurement_client.get_pending_purchase_orders(tenant_id, limit=100)
+            if pos_result and isinstance(pos_result, dict):
+                pos = pos_result.get("items", [])
+                # Count deliveries expected today
+                from datetime import datetime, timezone
+                today_start = datetime.now(timezone.utc).replace(hour=0, minute=0, second=0, microsecond=0)
+                today_end = today_start.replace(hour=23, minute=59, second=59)
+
+                deliveries_today = 0
+                for po in pos:
+                    expected_date = po.get("expected_delivery_date")
+                    if expected_date:
+                        if isinstance(expected_date, str):
+                            expected_date = datetime.fromisoformat(expected_date.replace('Z', '+00:00'))
+                        if today_start <= expected_date <= today_end:
+                            deliveries_today += 1
+
+                delivery_data = {"deliveries_today": deliveries_today}
+        except Exception as e:
+            logger.warning(f"Failed to fetch delivery data: {e}")
+
+        # Savings data - Calculate from recent PO price optimizations
+        savings_data = {}
+        try:
+            # Get recent POs (last 7 days) and sum up optimization savings
+            from datetime import datetime, timedelta, timezone
+            seven_days_ago = datetime.now(timezone.utc) - timedelta(days=7)
+
+            pos_result = await procurement_client.get_pending_purchase_orders(tenant_id, limit=200)
+            if pos_result and isinstance(pos_result, dict):
+                pos = pos_result.get("items", [])
+
+                weekly_savings = 0
+                # Calculate savings from price optimization
+                for po in pos:
+                    # Check if PO was created in last 7 days
+                    created_at = po.get("created_at")
+                    if created_at:
+                        if isinstance(created_at, str):
+                            created_at = datetime.fromisoformat(created_at.replace('Z', '+00:00'))
+                        if created_at >= seven_days_ago:
+                            # Sum up savings from optimization
+                            optimization_data = po.get("optimization_data", {})
+                            if isinstance(optimization_data, dict):
+                                savings = optimization_data.get("savings", 0) or 0
+                                weekly_savings += float(savings)
+
+                # Default trend percentage (would need historical data for real trend)
                 savings_data = {
-            "weekly_savings": 124,
-            "trend_percentage": 12
+                    "weekly_savings": round(weekly_savings, 2),
+                    "trend_percentage": 12 if weekly_savings > 0 else 0
                 }
+            else:
+                savings_data = {"weekly_savings": 0, "trend_percentage": 0}
+        except Exception as e:
+            logger.warning(f"Failed to calculate savings data: {e}")
+            savings_data = {"weekly_savings": 0, "trend_percentage": 0}
+
+        # Merge delivery data into inventory data
+        inventory_data.update(delivery_data)
 
         # Calculate insights
         insights = await dashboard_service.calculate_insights(