refactor(api): TOML 配置 SSOT、统一错误契约、Auth/事务加固与可观测性 (#33)

配置 SSOT（TOML + .env）
统一错误契约
Auth 与事务边界
Redis / Celery 可靠性:业务 Redis（DB/0）与 Celery broker/backend（DB/1）显式拆分；连接池、sync client
可观测性（OpenTelemetry + LGTM）

api/.agents/skills/redis-development/rules/data-transactions.md

@@ -0,0 +1,74 @@
+---
+title: Use Transactions for Atomic Multi-Command Operations
+impact: MEDIUM
+impactDescription: Prevents race conditions and data inconsistency
+tags: transactions, multi, exec, atomicity
+description: Use Transactions for Atomic Multi-Command Operations
+alwaysApply: true
+---
+
+## Use Transactions for Atomic Multi-Command Operations
+
+Use the `MULTI`/`EXEC` commands to create a transaction when you need to execute multiple commands atomically. No other client requests will be processed while the transaction is executing, preventing other clients from modifying the keys used in the transaction and avoiding inconsistent data.
+
+**Correct:** Use transactions when multiple related keys must be updated together.
+
+**Python** (redis-py):
+```python
+import redis
+
+client = redis.Redis(host='localhost', port=6379)
+
+# Transaction ensures all commands execute atomically
+pipe = client.pipeline(transaction=True)
+pipe.set("person:1:name", "Alex")
+pipe.set("person:1:rank", "Captain")
+pipe.set("person:1:serial", "AB1234")
+pipe.execute()  # All commands execute as one atomic unit
+```
+
+**Java** (Jedis):
+```java
+import redis.clients.jedis.UnifiedJedis;
+import redis.clients.jedis.Transaction;
+
+try (UnifiedJedis jedis = new UnifiedJedis("redis://localhost:6379")) {
+    Transaction tran = (Transaction) jedis.multi();
+
+    tran.set("person:1:name", "Alex");
+    tran.set("person:1:rank", "Captain");
+    tran.set("person:1:serial", "AB1234");
+
+    tran.exec();  // All commands execute atomically
+}
+```
+
+**Incorrect:** Executing related commands individually when atomicity is required.
+
+**Python** (redis-py):
+```python
+import redis
+
+client = redis.Redis(host='localhost', port=6379)
+
+# BAD when atomicity matters - another client could read partial state
+client.set("person:1:name", "Alex")
+# Another client could read here and see incomplete data
+client.set("person:1:rank", "Captain")
+client.set("person:1:serial", "AB1234")
+```
+
+**When to use transactions:**
+- Multiple keys must be updated as a single atomic unit
+- Other clients reading partial state would cause bugs
+- Implementing patterns like "transfer balance between accounts"
+
+**When transactions are NOT needed:**
+- Independent operations that don't need to be atomic
+- Single-command operations (already atomic)
+- When using pipelining purely for performance (use `pipeline(transaction=False)`)
+
+**Note:** Transactions add overhead. Only use them when atomicity is actually required.
+
+Reference: [Transactions](https://redis.io/docs/latest/develop/interact/transactions/)
+