fix(test): 修复测试和添加数据库迁移

测试修复：
- 修复集成测试中的重复键冲突问题
- 移除 JSON 中多余的尾随逗号
- 新增 inprocess_transport_test.go
- 更新 haiku 模型映射测试用例

数据库迁移：
- 026: 运营指标聚合表
- 027: 使用量与计费一致性约束

backend/internal/repository/github_release_service_test.go

@@ -49,7 +49,7 @@ func (s *GitHubReleaseServiceSuite) TearDownTest() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestDownloadFile_EnforcesMaxSize_ContentLength() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Length", "100")
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write(bytes.Repeat([]byte("a"), 100))
@@ -68,7 +68,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_EnforcesMaxSize_ContentLeng
 }
 
 func (s *GitHubReleaseServiceSuite) TestDownloadFile_EnforcesMaxSize_Chunked() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		// Force chunked encoding (unknown Content-Length) by flushing headers before writing.
 		w.WriteHeader(http.StatusOK)
 		if fl, ok := w.(http.Flusher); ok {
@@ -95,7 +95,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_EnforcesMaxSize_Chunked() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestDownloadFile_Success() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusOK)
 		if fl, ok := w.(http.Flusher); ok {
 			fl.Flush()
@@ -123,7 +123,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_Success() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestDownloadFile_404() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusNotFound)
 	}))
 
@@ -140,7 +140,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_404() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_Success() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write([]byte("sum"))
 	}))
@@ -155,7 +155,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_Success() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_Non200() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusInternalServerError)
 	}))
 
@@ -168,7 +168,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_Non200() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestDownloadFile_ContextCancel() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		<-r.Context().Done()
 	}))
 
@@ -195,7 +195,7 @@ func (s *GitHubReleaseServiceSuite) TestDownloadFile_InvalidURL() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestDownloadFile_InvalidDestPath() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write([]byte("content"))
 	}))
@@ -233,7 +233,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_Success() {
 		]
 	}`
 
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		require.Equal(s.T(), "/repos/test/repo/releases/latest", r.URL.Path)
 		require.Equal(s.T(), "application/vnd.github.v3+json", r.Header.Get("Accept"))
 		require.Equal(s.T(), "Sub2API-Updater", r.Header.Get("User-Agent"))
@@ -258,7 +258,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_Success() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_Non200() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusNotFound)
 	}))
 
@@ -274,7 +274,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_Non200() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_InvalidJSON() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(http.StatusOK)
 		_, _ = w.Write([]byte("not valid json"))
 	}))
@@ -290,7 +290,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_InvalidJSON() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_ContextCancel() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		<-r.Context().Done()
 	}))
 
@@ -308,7 +308,7 @@ func (s *GitHubReleaseServiceSuite) TestFetchLatestRelease_ContextCancel() {
 }
 
 func (s *GitHubReleaseServiceSuite) TestFetchChecksumFile_ContextCancel() {
-	s.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	s.srv = newLocalTestServer(s.T(), http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		<-r.Context().Done()
 	}))