feat: 0.2.27 - 抽离数据库基础设施模块

- 新增 ias-db crate，集中管理 PostgreSQL 连接池和 SQLx 迁移
- 迁移 ias-service/migrations 到 ias-db/migrations
- ias-main 改用 ias_db::connect_db()，ias-service 只接 PgPool
- 新增操作日志 HTTP 查询接口 (GET /v1/logs, GET /v1/logs/{id})
- 新增操作日志 Web 前端页面，支持按级别/模块/关键词筛选
- 消息队列关键节点增加操作日志写入
- ias-mail 新增 mark_remote_message_seen，IMAP 已读同步
- 工作流配置加载改为文件级容错 (load_configs_with_warnings)
- ias-context 工具调用说明更新为 query_api_docs + call_http_api
- 新增高德地图地理编码 HTTP 能力配置

模块版本: ias-db 0.1.0, ias-ai 0.1.14, ias-context 0.1.6, ias-http 0.1.15, ias-mail 0.1.16, ias-service 0.1.25, ias-main 0.2.27

ias-db/migrations/20260706017000_version_update_notifications.sql

@@ -0,0 +1,28 @@
+CREATE TABLE ias_version_notifications (
+    version VARCHAR(64) PRIMARY KEY,
+    notified_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    recipient_count INTEGER NOT NULL DEFAULT 0
+);
+
+INSERT INTO ias_upgrade_logs (
+    version,
+    released_at,
+    title,
+    description,
+    changes
+) VALUES (
+    '0.1.6',
+    '2026-07-06T00:00:00+08:00',
+    'Version update notifications and changelog pages',
+    'Added HTTP upgrade-log pages and one-time startup notifications that tell users which version the service updated to.',
+    '[
+        "Added HTTP-rendered upgrade log pages at /updates and /updates/{version}.",
+        "Added one-time startup notifications for new service versions, including the updated version number and an HTTP upgrade-log link.",
+        "Added persisted version notification state so users are not notified repeatedly after ordinary restarts.",
+        "Persisted the 0.1.6 upgrade record."
+    ]'::jsonb
+) ON CONFLICT (version) DO UPDATE SET
+    released_at = EXCLUDED.released_at,
+    title = EXCLUDED.title,
+    description = EXCLUDED.description,
+    changes = EXCLUDED.changes;