refactor: CSP nonce替代unsafe-inline, HSTS始终启用, router/api拆分, 管理后台+用户设置页拆分, DB健康降级, 时区配置, UID统一解析, CI接入

审计修复:
- CSP: unsafe-inline移除, nonce替代; unsafe-eval保留供Vditor使用
- HSTS: 始终启用(不再依赖release模式)
- Controller Exp: common.GetGinExp包装, 不再直接读context
- UID解析: common.ParseUIDParam统一, follow/admin controller改用

重构:
- router/api.go(198行)拆为7个域文件: auth/settings/posts/comments/reactions/social/studio
- 管理后台站点设置: 单页拆为4个子页(brand/security/registration/content)+子菜单
- 前台用户设置页: 1201行拆为6个独立模板+6个独立JS文件

新增:
- DB健康检测中间件(middleware/db_health.go): 5s ping+降级页面
- 时区配置: config.yaml server.timezone→time.Local初始化
- .gitea/workflows/ci.yml: strict模式CI流水线

.gitea/workflows/ci.yml

@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  lint:
+    name: Lint + Build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.26"
+
+      - name: Cache Go modules
+        uses: actions/cache@v4
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('go.sum') }}
+          restore-keys: ${{ runner.os }}-go-
+
+      - name: Install tools
+        run: |
+          go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.12.2
+          go install mvdan.cc/gofumpt@latest
+          go install golang.org/x/tools/cmd/goimports@latest
+
+      - name: CI (strict)
+        run: bash scripts/ci.sh --strict