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/claude_usage_service.go

@@ -1,59 +1,59 @@
-package repository
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"io"
-	"net/http"
-	"time"
-
-	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
-	"github.com/Wei-Shaw/sub2api/internal/service"
-)
-
-const defaultClaudeUsageURL = "https://api.anthropic.com/api/oauth/usage"
-
-type claudeUsageService struct {
-	usageURL string
-}
-
-func NewClaudeUsageFetcher() service.ClaudeUsageFetcher {
-	return &claudeUsageService{usageURL: defaultClaudeUsageURL}
-}
-
-func (s *claudeUsageService) FetchUsage(ctx context.Context, accessToken, proxyURL string) (*service.ClaudeUsageResponse, error) {
-	client, err := httpclient.GetClient(httpclient.Options{
-		ProxyURL: proxyURL,
-		Timeout:  30 * time.Second,
-	})
-	if err != nil {
-		client = &http.Client{Timeout: 30 * time.Second}
-	}
-
-	req, err := http.NewRequestWithContext(ctx, "GET", s.usageURL, nil)
-	if err != nil {
-		return nil, fmt.Errorf("create request failed: %w", err)
-	}
-
-	req.Header.Set("Authorization", "Bearer "+accessToken)
-	req.Header.Set("anthropic-beta", "oauth-2025-04-20")
-
-	resp, err := client.Do(req)
-	if err != nil {
-		return nil, fmt.Errorf("request failed: %w", err)
-	}
-	defer func() { _ = resp.Body.Close() }()
-
-	if resp.StatusCode != http.StatusOK {
-		body, _ := io.ReadAll(resp.Body)
-		return nil, fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(body))
-	}
-
-	var usageResp service.ClaudeUsageResponse
-	if err := json.NewDecoder(resp.Body).Decode(&usageResp); err != nil {
-		return nil, fmt.Errorf("decode response failed: %w", err)
-	}
-
-	return &usageResp, nil
-}
+package repository
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/httpclient"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+)
+
+const defaultClaudeUsageURL = "https://api.anthropic.com/api/oauth/usage"
+
+type claudeUsageService struct {
+	usageURL string
+}
+
+func NewClaudeUsageFetcher() service.ClaudeUsageFetcher {
+	return &claudeUsageService{usageURL: defaultClaudeUsageURL}
+}
+
+func (s *claudeUsageService) FetchUsage(ctx context.Context, accessToken, proxyURL string) (*service.ClaudeUsageResponse, error) {
+	client, err := httpclient.GetClient(httpclient.Options{
+		ProxyURL: proxyURL,
+		Timeout:  30 * time.Second,
+	})
+	if err != nil {
+		client = &http.Client{Timeout: 30 * time.Second}
+	}
+
+	req, err := http.NewRequestWithContext(ctx, "GET", s.usageURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("create request failed: %w", err)
+	}
+
+	req.Header.Set("Authorization", "Bearer "+accessToken)
+	req.Header.Set("anthropic-beta", "oauth-2025-04-20")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("request failed: %w", err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(resp.Body)
+		return nil, fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(body))
+	}
+
+	var usageResp service.ClaudeUsageResponse
+	if err := json.NewDecoder(resp.Body).Decode(&usageResp); err != nil {
+		return nil, fmt.Errorf("decode response failed: %w", err)
+	}
+
+	return &usageResp, nil
+}