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-hash-field-expiry.md

@@ -0,0 +1,62 @@
+---
+title: Use Hash Field Expiration for Per-Field TTL
+impact: MEDIUM
+impactDescription: Fine-grained expiration without managing timers
+tags: hash, expiration, ttl, hexpire
+description: Use Hash Field Expiration for Per-Field TTL
+alwaysApply: true
+---
+
+## Use Hash Field Expiration for Per-Field TTL
+
+Use hash field expiration (Redis 7.4+) to delete individual fields automatically from a hash after a specific period of time. This is useful for caching scenarios where different fields have different lifetimes, and is easier than managing expiration from your own code.
+
+**Correct:** Use HEXPIRE to set per-field TTL on hash fields.
+
+**Python** (redis-py):
+```python
+import redis
+
+client = redis.Redis(host='localhost', port=6379)
+
+# Set hash fields
+client.hset("sensor:sensor1", mapping={
+    "air_quality": "256",
+    "battery_level": "89"
+})
+
+# Set 60-second TTL on specific fields (Redis 7.4+)
+client.hexpire("sensor:sensor1", 60, "air_quality", "battery_level")
+```
+
+**Java** (Jedis):
+```java
+import redis.clients.jedis.UnifiedJedis;
+import java.util.Map;
+import java.util.HashMap;
+
+try (UnifiedJedis jedis = new UnifiedJedis("redis://localhost:6379")) {
+    Map<String, String> hashFields = new HashMap<>();
+    hashFields.put("air_quality", "256");
+    hashFields.put("battery_level", "89");
+
+    jedis.hset("sensor:sensor1", hashFields);
+    
+    // Set 60-second TTL on specific fields (Redis 7.4+)
+    jedis.hexpire("sensor:sensor1", 60, "air_quality", "battery_level");
+}
+```
+
+**When to use:**
+- Sensor data or metrics that become stale after a period
+- Session attributes where different fields have different lifetimes
+- Cached values within a hash that should auto-expire independently
+- Temporary flags or tokens stored alongside persistent data
+
+**When NOT needed:**
+- Persistent user profiles or configuration
+- Data where the entire hash should expire together (use `EXPIRE` on the key instead)
+- Fields managed by application logic with explicit deletion
+
+Reference: [HEXPIRE command](https://redis.io/docs/latest/commands/hexpire/)
+