feat(lyra)!: 接入分类查询并集中组装依赖

- 使用 Squirrel 与 sqlx 实现分类查询
- 集中组装依赖并向 handler 注入 model 接口
- 显式转换分类响应 DTO，统一空列表输出
- 补充路由与 handler 测试，同步架构文档

BREAKING CHANGE: 将 GET /hello 替换为 GET /test，响应由问候字符串改为分类列表

go/projects/lyra/internal/router/router_test.go

@@ -10,19 +10,68 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-func TestHelloRoute(t *testing.T) {
-	gin.SetMode(gin.TestMode)
-	engine := gin.New()
-	router.RegisterRoutes(engine)
+const (
+	stubStatus = http.StatusAccepted
+	stubBody   = "injected test handler"
+)
 
+// newStubHandlers 返回记录调用次数并输出固定状态码与响应体的替身处理器。
+func newStubHandlers(calls *int) router.Handlers {
+	return router.Handlers{
+		TestHandler: func(c *gin.Context) {
+			*calls++
+			c.String(stubStatus, stubBody)
+		},
+	}
+}
+
+func TestRouteInvokesInjectedHandler(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	var calls int
+	engine := gin.New()
+	router.RegisterRoutes(engine, newStubHandlers(&calls))
+
 	recorder := httptest.NewRecorder()
-	engine.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/hello", nil))
+	engine.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/test", nil))
 
-	if recorder.Code != http.StatusOK {
-		t.Fatalf("GET /hello status = %d, want %d", recorder.Code, http.StatusOK)
+	if calls != 1 {
+		t.Fatalf("GET /test 替身调用次数 = %d, want 1", calls)
+	}
+	if recorder.Code != stubStatus {
+		t.Fatalf("GET /test status = %d, want %d", recorder.Code, stubStatus)
+	}
+	if got := recorder.Body.String(); got != stubBody {
+		t.Fatalf("GET /test body = %q, want %q", got, stubBody)
 	}
-	want := `{"success":true,"data":"Hello, World!"}`
-	if got := recorder.Body.String(); got != want {
-		t.Fatalf("GET /hello body = %q, want %q", got, want)
+}
+
+func TestRouteSkipsHandlerForUnknownPathOrMethod(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	tests := []struct {
+		name   string
+		method string
+		path   string
+	}{
+		{name: "未知路径", method: http.MethodGet, path: "/unknown"},
+		{name: "不支持的方法", method: http.MethodPost, path: "/test"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var calls int
+			engine := gin.New()
+			router.RegisterRoutes(engine, newStubHandlers(&calls))
+
+			recorder := httptest.NewRecorder()
+			engine.ServeHTTP(recorder, httptest.NewRequest(tt.method, tt.path, nil))
+
+			if calls != 0 {
+				t.Fatalf("%s %s 替身调用次数 = %d, want 0", tt.method, tt.path, calls)
+			}
+			if recorder.Code != http.StatusNotFound {
+				t.Fatalf("%s %s status = %d, want %d", tt.method, tt.path, recorder.Code, http.StatusNotFound)
+			}
+		})
 	}
 }