docs: 迁移收尾——部署信息同步到 Oracle 新机 129.146.26.249

- backend/.env.example: AI 网关地址 129.146.203.203 → 129.146.26.249；
  MariaDB 注释段更新为生产实际（garmin 专用账号 @ 127.0.0.1:3306，socket 已不用）
- README: 生产数据层/数据库说明改为 Oracle 新机本地 MariaDB 10.3
- docs/REQUIREMENTS: 部署目标 NAS → Oracle 新机；公网方式 frp 隧道 → gunicorn 直绑 8123
- docs/ARCHITECTURE: 部署架构改为真实生产栈（Flask+gunicorn+MariaDB+SPA）

backend/.env.example

@@ -8,12 +8,13 @@ DB_TYPE=sqlite
 # SQLite file (used when DB_TYPE=sqlite)
 DATABASE_PATH=./data/health.db
 
-# MariaDB (used when DB_TYPE=mariadb) — runs on the NAS
-# MARIADB_SOCKET=/run/mysqld/mysqld10.sock
+# MariaDB (used when DB_TYPE=mariadb) — production DB on the Oracle server
+# (129.146.26.249, local MariaDB 10.3). Dedicated account over TCP 127.0.0.1;
+# MARIADB_SOCKET is only needed if TCP auth is disabled for the app user.
 # MARIADB_HOST=127.0.0.1
 # MARIADB_PORT=3306
-# MARIADB_USER=root
-# MARIADB_PASSWORD=your_nas_mariadb_root_password
+# MARIADB_USER=garmin
+# MARIADB_PASSWORD=your_production_mariadb_password
 # MARIADB_DATABASE=garmin_health_lab
 
 # --- Auth ---
@@ -36,7 +37,7 @@ CORS_ORIGIN=http://localhost:3000,http://localhost:5173
 # absorbs single-vendor quota limits. Reached directly, bypassing any local
 # HTTP proxy. NOTE: its NVIDIA upstream is a large reasoning model — replies
 # can take 2-3 minutes, so set AI_TIMEOUT_SECONDS accordingly.
-AI_GATEWAY_BASE_URL=http://129.146.203.203:5100/v1
+AI_GATEWAY_BASE_URL=http://129.146.26.249:5100/v1
 AI_GATEWAY_TOKEN=
 AI_GATEWAY_MODEL=ai-gateway-auto