feat(yun8_sync): add API pipeline automating full freight flow (18 interfaces + SQL)

Implements the "运输流程" collection from yun8.postman_collection.json as a
Python pipeline: driver-side order accept/load/unload -> freight accounting
-> payment, with SQL writes, driven by yun8_sync/config.yaml
(api/auth/accounting/payment/database/sql/dianyuntong sections).

yun8_sync/db.py

@@ -0,0 +1,53 @@
+"""
+数据库操作
+==========
+封装 ntocc.base_gd_mft_file 表的 INSERT 操作。
+"""
+
+import pymysql
+
+
+class Database:
+    """MySQL 数据库写入"""
+
+    def __init__(self, config: dict):
+        db = config["database"]
+        self.conn_kwargs = {
+            "host": db["host"],
+            "port": db.get("port", 3306),
+            "user": db["user"],
+            "password": db["password"],
+            "database": db["database"],
+            "charset": db.get("charset", "utf8mb4"),
+        }
+        sql_cfg = config["sql"]
+        self.file_name_template = sql_cfg["file_name_template"]
+        self.sql_template = sql_cfg["template"]
+
+    def build_sql(self, file_prefix: str, pay_no: str) -> str:
+        """拼接完整 SQL（dry-run / 日志用）"""
+        file_name = self.file_name_template.format(file_prefix=file_prefix)
+        return self.sql_template.format(file_name=file_name, pay_no=pay_no)
+
+    def insert(self, file_prefix: str, pay_no: str) -> int:
+        """执行 INSERT，返回 affected rows"""
+        sql = self.build_sql(file_prefix, pay_no)
+        conn = pymysql.connect(**self.conn_kwargs)
+        try:
+            with conn.cursor() as cur:
+                cur.execute(sql)
+            conn.commit()
+            return cur.rowcount
+        finally:
+            conn.close()
+
+    def execute(self, sql: str) -> int:
+        """执行任意 SQL，返回 affected rows"""
+        conn = pymysql.connect(**self.conn_kwargs)
+        try:
+            with conn.cursor() as cur:
+                cur.execute(sql)
+            conn.commit()
+            return cur.rowcount
+        finally:
+            conn.close()