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/internal/repository/db_pool_test.go

@@ -1,50 +1,50 @@
-package repository
-
-import (
-	"database/sql"
-	"testing"
-	"time"
-
-	"github.com/Wei-Shaw/sub2api/internal/config"
-	"github.com/stretchr/testify/require"
-
-	_ "github.com/lib/pq"
-)
-
-func TestBuildDBPoolSettings(t *testing.T) {
-	cfg := &config.Config{
-		Database: config.DatabaseConfig{
-			MaxOpenConns:           50,
-			MaxIdleConns:           10,
-			ConnMaxLifetimeMinutes: 30,
-			ConnMaxIdleTimeMinutes: 5,
-		},
-	}
-
-	settings := buildDBPoolSettings(cfg)
-	require.Equal(t, 50, settings.MaxOpenConns)
-	require.Equal(t, 10, settings.MaxIdleConns)
-	require.Equal(t, 30*time.Minute, settings.ConnMaxLifetime)
-	require.Equal(t, 5*time.Minute, settings.ConnMaxIdleTime)
-}
-
-func TestApplyDBPoolSettings(t *testing.T) {
-	cfg := &config.Config{
-		Database: config.DatabaseConfig{
-			MaxOpenConns:           40,
-			MaxIdleConns:           8,
-			ConnMaxLifetimeMinutes: 15,
-			ConnMaxIdleTimeMinutes: 3,
-		},
-	}
-
-	db, err := sql.Open("postgres", "host=127.0.0.1 port=5432 user=postgres sslmode=disable")
-	require.NoError(t, err)
-	t.Cleanup(func() {
-		_ = db.Close()
-	})
-
-	applyDBPoolSettings(db, cfg)
-	stats := db.Stats()
-	require.Equal(t, 40, stats.MaxOpenConnections)
-}
+package repository
+
+import (
+	"database/sql"
+	"testing"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/stretchr/testify/require"
+
+	_ "github.com/lib/pq"
+)
+
+func TestBuildDBPoolSettings(t *testing.T) {
+	cfg := &config.Config{
+		Database: config.DatabaseConfig{
+			MaxOpenConns:           50,
+			MaxIdleConns:           10,
+			ConnMaxLifetimeMinutes: 30,
+			ConnMaxIdleTimeMinutes: 5,
+		},
+	}
+
+	settings := buildDBPoolSettings(cfg)
+	require.Equal(t, 50, settings.MaxOpenConns)
+	require.Equal(t, 10, settings.MaxIdleConns)
+	require.Equal(t, 30*time.Minute, settings.ConnMaxLifetime)
+	require.Equal(t, 5*time.Minute, settings.ConnMaxIdleTime)
+}
+
+func TestApplyDBPoolSettings(t *testing.T) {
+	cfg := &config.Config{
+		Database: config.DatabaseConfig{
+			MaxOpenConns:           40,
+			MaxIdleConns:           8,
+			ConnMaxLifetimeMinutes: 15,
+			ConnMaxIdleTimeMinutes: 3,
+		},
+	}
+
+	db, err := sql.Open("postgres", "host=127.0.0.1 port=5432 user=postgres sslmode=disable")
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = db.Close()
+	})
+
+	applyDBPoolSettings(db, cfg)
+	stats := db.Stats()
+	require.Equal(t, 40, stats.MaxOpenConnections)
+}