feat(customer): 新增ICC客户信息同步功能 - OAuth2密码模式鉴权拉取org_base客户、按icc_code幂等upsert写入并记录icc_sync_log，注册每10分钟定时任务；客户档案管理页新增手动'同步客户'按钮（POST /api/customers/sync/icc），同步后自动刷新列表与统计；customer表新增icc_code字段及唯一索引，同步db_seed与设计文档

database/db_init.sql

@@ -191,6 +191,7 @@ DROP TABLE IF EXISTS customer CASCADE;
 CREATE TABLE customer (
     id              BIGSERIAL PRIMARY KEY,
     customer_no     VARCHAR(64)  NOT NULL UNIQUE,
+    icc_code        VARCHAR(64),
     customer_name   VARCHAR(128) NOT NULL,
     province        VARCHAR(64),
     city            VARCHAR(64),
@@ -209,6 +210,7 @@ CREATE TABLE customer (
 COMMENT ON TABLE  customer IS '客户信息表';
 COMMENT ON COLUMN customer.id              IS '自增主键';
 COMMENT ON COLUMN customer.customer_no     IS '客户业务编号（KH+YYYYMMDD+3位序号）';
+COMMENT ON COLUMN customer.icc_code        IS 'ICC客户编码（ICC平台 orgCode，同步来源）';
 COMMENT ON COLUMN customer.customer_name   IS '客户名称';
 COMMENT ON COLUMN customer.province        IS '省';
 COMMENT ON COLUMN customer.city            IS '市';
@@ -227,6 +229,7 @@ CREATE INDEX idx_customer_name     ON customer (customer_name);
 CREATE INDEX idx_customer_salesman ON customer (salesman_id);
 CREATE INDEX idx_customer_status   ON customer (status);
 CREATE INDEX idx_customer_region   ON customer (province, city, district);
+CREATE UNIQUE INDEX uk_customer_icc_code ON customer (icc_code);
 CREATE TRIGGER trg_customer_updated_at BEFORE UPDATE ON customer
     FOR EACH ROW EXECUTE FUNCTION trigger_set_updated_at();