refactor: serve static frontend with Go APIs

backend/internal/httpapi/method_compat.go

@@ -12,10 +12,10 @@ type routeMethodPattern struct {
 	allow   []string
 }
 
-// WithRouteMethodCompatibility applies the method behavior that Next derives
-// from app route exports. It sits outside authentication so OPTIONS never
-// depends on runtime configuration and HEAD executes the corresponding GET
-// semantics while suppressing the response body.
+// WithRouteMethodCompatibility applies the legacy-compatible method matrix
+// for the checked-in public HTTP contract. It sits outside authentication so
+// OPTIONS never depends on runtime configuration and HEAD executes the
+// corresponding GET semantics while suppressing the response body.
 func WithRouteMethodCompatibility(next http.Handler) http.Handler {
 	patterns := routeMethodPatterns(GoRouteSurface())
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {