feat: show local Docker images on project detail page

- Add GET /api/projects/{id}/images endpoint returning local images matching the project
- Add ListImagesByRef with tag, size, and created timestamp to Docker client
- Display images table on project page with tag, ID (truncated), size (MB), and created date
- Only shown when Docker is available and images exist locally

internal/api/router.go

@@ -204,6 +204,7 @@ func (s *Server) Router() chi.Router {
 				r.Get("/stages/{stage}/env", s.listStageEnv)
 				r.Get("/stages/{stage}/instances", s.listInstances)
 				r.Get("/stages/{stage}/instances/{iid}/stats", s.getInstanceStats)
+				r.Get("/images", s.listProjectImages)
 				r.Get("/volumes", s.listVolumes)
 				r.Get("/volumes/{volId}/browse", s.browseVolume)
 				r.Get("/volumes/{volId}/download", s.downloadVolume)