feat: chat agent knows current page context (order/product)

Frontend: Layout extracts order/product UUID from URL path and passes
to ChatPanel as contextType/contextId. When on /orders/{uuid}, the
chat knows which order you're viewing.

Backend: System prompt now loads actual entity data for the context:
- Order: order_number, status, line counts (completed/processing/failed)
- Product: name, PIM-ID, category, STEP file status

The AI understands "this order", "current product" etc. Example:
"What's the status of this order?" → agent knows you mean SA-2026-00164

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/services/chat_service.py

@@ -682,8 +682,60 @@ async def chat_with_agent(
 
     # Build context-aware system prompt
     system_content = SYSTEM_PROMPT
-    if context_type and context_id:
-        system_content += f"\n\nCurrent context: {context_type} {context_id}"
+
+    # Load entity details for the current page context
+    if context_type == "order" and context_id:
+        try:
+            ctx_result = await db.execute(
+                text("""
+                    SELECT o.order_number, o.status, o.notes, o.created_at,
+                           COUNT(ol.id) AS line_count,
+                           COUNT(ol.id) FILTER (WHERE ol.render_status = 'completed') AS completed,
+                           COUNT(ol.id) FILTER (WHERE ol.render_status = 'processing') AS processing,
+                           COUNT(ol.id) FILTER (WHERE ol.render_status = 'failed') AS failed,
+                           COUNT(ol.id) FILTER (WHERE ol.render_status = 'pending') AS pending
+                    FROM orders o
+                    LEFT JOIN order_lines ol ON ol.order_id = o.id
+                    WHERE o.id = :ctx_id AND o.tenant_id = :tid
+                    GROUP BY o.id
+                """),
+                {"ctx_id": context_id, "tid": tenant_id},
+            )
+            row = ctx_result.mappings().first()
+            if row:
+                system_content += (
+                    f"\n\nThe user is currently viewing order {row['order_number']} "
+                    f"(ID: {context_id}, status: {row['status']}, "
+                    f"{row['line_count']} lines: {row['completed']} completed, "
+                    f"{row['processing']} processing, {row['failed']} failed, "
+                    f"{row['pending']} pending). "
+                    f"When the user says 'this order' or 'current order', they mean {row['order_number']} ({context_id})."
+                )
+        except Exception:
+            system_content += f"\n\nThe user is viewing order {context_id}."
+    elif context_type == "product" and context_id:
+        try:
+            ctx_result = await db.execute(
+                text("""
+                    SELECT p.name, p.pim_id, p.category_key, p.baureihe,
+                           CASE WHEN p.cad_file_id IS NOT NULL THEN true ELSE false END AS has_step
+                    FROM products p
+                    WHERE p.id = :ctx_id AND p.tenant_id = :tid
+                """),
+                {"ctx_id": context_id, "tid": tenant_id},
+            )
+            row = ctx_result.mappings().first()
+            if row:
+                system_content += (
+                    f"\n\nThe user is currently viewing product '{row['name']}' "
+                    f"(ID: {context_id}, PIM-ID: {row['pim_id']}, "
+                    f"category: {row['category_key']}, "
+                    f"has STEP: {row['has_step']}). "
+                    f"When the user says 'this product' or 'current product', they mean '{row['name']}' ({context_id})."
+                )
+        except Exception:
+            system_content += f"\n\nThe user is viewing product {context_id}."
+
     system_content += f"\n\nThe user's tenant_id is '{tenant_id}'. Always filter queries by this tenant_id."
 
     messages: list[dict] = [{"role": "system", "content": system_content}]