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/conn-pipelining.md

@@ -0,0 +1,58 @@
+---
+title: Use Pipelining for Bulk Operations
+impact: HIGH
+impactDescription: Reduces round trips, 5-10x faster for batch operations
+tags: pipelining, batch, performance, round-trips
+description: Use Pipelining for Bulk Operations
+alwaysApply: true
+---
+
+## Use Pipelining for Bulk Operations
+
+Batch multiple commands into a single round trip to reduce network latency.
+
+**Correct:** Use pipeline for multiple commands.
+
+**Python** (redis-py):
+```python
+# Good: Single round trip for multiple commands
+pipe = redis.pipeline()
+for user_id in user_ids:
+    pipe.get(f"user:{user_id}")
+results = pipe.execute()
+```
+
+**Java** (Jedis):
+```java
+import redis.clients.jedis.Pipeline;
+
+// Good: Buffer commands and send as single batch
+Pipeline pipe = (Pipeline) jedis.pipelined();
+
+pipe.set("person:1:name", "Alex");
+pipe.set("person:1:rank", "Captain");
+pipe.set("person:1:serial", "AB1234");
+
+pipe.sync();
+```
+
+**Incorrect:** Sequential commands in a loop.
+
+**Python** (redis-py):
+```python
+# Bad: N round trips
+results = []
+for user_id in user_ids:
+    results.append(redis.get(f"user:{user_id}"))
+```
+
+**Java** (Jedis):
+```java
+// Bad: 3 separate round trips
+jedis.set("person:1:name", "Alex");
+jedis.set("person:1:rank", "Captain");
+jedis.set("person:1:serial", "AB1234");
+```
+
+Reference: [Redis Pipelining](https://redis.io/docs/latest/develop/use/pipelining/)
+