feat(crm): add customer list column filter builder.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/tests/test_crm_customer_list_filters.py

@@ -0,0 +1,59 @@
+"""CRM 客户列表列头/导出共用过滤条件拼装单测。"""
+from __future__ import annotations
+
+from sqlalchemy.dialects import mysql
+
+from app.services.crm.customer_list_filters import build_customer_column_filters
+
+
+def _compile(clause) -> str:
+    return str(
+        clause.compile(dialect=mysql.dialect(), compile_kwargs={"literal_binds": True})
+    ).lower()
+
+
+def test_level_in_adds_in_clause():
+    filters = build_customer_column_filters(level_in="key,normal")
+    assert len(filters) == 1
+    sql = _compile(filters[0])
+    assert "level" in sql
+    assert "in (" in sql
+    assert "key" in sql
+    assert "normal" in sql
+
+
+def test_customer_name_fuzzy():
+    filters = build_customer_column_filters(customer_name="三峡")
+    assert len(filters) == 1
+    sql = _compile(filters[0])
+    assert "customer_name" in sql
+    assert "三峡" in sql
+
+
+def test_deal_amount_between_min_only():
+    filters = build_customer_column_filters(
+        deal_amount_op="between",
+        deal_amount_min="100",
+    )
+    assert len(filters) == 1
+    sql = _compile(filters[0])
+    assert "deal_amount" in sql
+    assert ">=" in sql
+    assert "100" in sql
+
+
+def test_begin_end_time_create_time():
+    filters = build_customer_column_filters(
+        begin_time="2026-01-01",
+        end_time="2026-01-31",
+    )
+    assert len(filters) >= 1
+    joined = " ".join(_compile(f) for f in filters)
+    assert "create_time" in joined
+    assert ">=" in joined
+    assert "2026-01-01" in joined
+
+
+def test_empty_params_yield_no_filters():
+    filters = build_customer_column_filters()
+    assert filters == []