feat: 客户列表按产品线分组展示 + 产品线筛选

- server.py: /api/customers 增加 product_id 筛选参数 + 返回 product_categories 字段
- index.html: 客户列表按产品线分组渲染(儿童益生菌/女性减肥益生菌/未关联) + 增加产品线筛选下拉

demo/web/server.py

@@ -243,21 +243,25 @@ def list_salespersons():
 def list_customers(
     salesperson_id: int | None = Query(None),
     intent_level: str | None = Query(None),
+    product_id: int | None = Query(None),
 ):
     conn = get_conn()
     try:
         with conn.cursor() as cur:
             sql = """
-                SELECT cu.id, cu.salesperson_id, s.name AS salesperson_name,
+                SELECT DISTINCT cu.id, cu.salesperson_id, s.name AS salesperson_name,
                     cu.customer_name, cu.industry, cu.intent_level,
                     cu.key_needs, cu.stage, cu.last_analysis,
                     c.display_name AS contact_display_name,
-                    max(m.created_at) AS last_message_at
+                    max(m.created_at) AS last_message_at,
+                    string_agg(DISTINCT p.category, ', ') AS product_categories
                 FROM customer cu
                 JOIN salesperson s ON s.id = cu.salesperson_id
                 JOIN contact c ON c.id = cu.contact_id
                 LEFT JOIN conversation conv ON conv.contact_id = c.id
                 LEFT JOIN message m ON m.conversation_id = conv.id
+                LEFT JOIN deal d ON d.customer_id = cu.id
+                LEFT JOIN product p ON p.id = d.product_id
             """
             conditions = []
             params = []
@@ -267,6 +271,9 @@ def list_customers(
             if intent_level is not None:
                 conditions.append("cu.intent_level = %s")
                 params.append(intent_level)
+            if product_id is not None:
+                conditions.append("d.product_id = %s")
+                params.append(product_id)
             if conditions:
                 sql += " WHERE " + " AND ".join(conditions)
             sql += """
@@ -286,6 +293,7 @@ def list_customers(
                     "last_analysis": r[8].isoformat() if r[8] else None,
                     "contact_display_name": r[9],
                     "last_message_at": r[10].isoformat() if r[10] else None,
+                    "product_categories": r[11],
                 }
                 for r in cur.fetchall()
             ]