feat: 品牌重命名 Sub2API -> TianShuAPI

- 前端: 所有界面显示、i18n 文本、组件中的品牌名称
- 后端: 服务层、设置默认值、邮件模板、安装向导
- 数据库: 迁移脚本注释
- 保持功能完全一致，仅更改品牌名称

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/migrations/007_add_user_allowed_groups.sql

@@ -1,20 +1,20 @@
--- Add user_allowed_groups join table to replace users.allowed_groups (BIGINT[]).
--- Phase 1: create table + backfill from the legacy array column.
-
-CREATE TABLE IF NOT EXISTS user_allowed_groups (
-    user_id     BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-    group_id    BIGINT NOT NULL REFERENCES groups(id) ON DELETE CASCADE,
-    created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
-    PRIMARY KEY (user_id, group_id)
-);
-
-CREATE INDEX IF NOT EXISTS idx_user_allowed_groups_group_id ON user_allowed_groups(group_id);
-
--- Backfill from the legacy users.allowed_groups array.
-INSERT INTO user_allowed_groups (user_id, group_id)
-SELECT u.id, x.group_id
-FROM users u
-CROSS JOIN LATERAL unnest(u.allowed_groups) AS x(group_id)
-JOIN groups g ON g.id = x.group_id
-WHERE u.allowed_groups IS NOT NULL
-ON CONFLICT DO NOTHING;
+-- Add user_allowed_groups join table to replace users.allowed_groups (BIGINT[]).
+-- Phase 1: create table + backfill from the legacy array column.
+
+CREATE TABLE IF NOT EXISTS user_allowed_groups (
+    user_id     BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    group_id    BIGINT NOT NULL REFERENCES groups(id) ON DELETE CASCADE,
+    created_at  TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (user_id, group_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_user_allowed_groups_group_id ON user_allowed_groups(group_id);
+
+-- Backfill from the legacy users.allowed_groups array.
+INSERT INTO user_allowed_groups (user_id, group_id)
+SELECT u.id, x.group_id
+FROM users u
+CROSS JOIN LATERAL unnest(u.allowed_groups) AS x(group_id)
+JOIN groups g ON g.id = x.group_id
+WHERE u.allowed_groups IS NOT NULL
+ON CONFLICT DO NOTHING;