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/docker.go

@@ -1,10 +1,46 @@
 package api
 
 import (
+	"errors"
 	"log/slog"
 	"net/http"
+
+	"github.com/go-chi/chi/v5"
+
+	"github.com/alexei/docker-watcher/internal/store"
 )
 
+// listProjectImages handles GET /api/projects/{id}/images.
+// Returns all local Docker images matching the project's image reference.
+func (s *Server) listProjectImages(w http.ResponseWriter, r *http.Request) {
+	id := chi.URLParam(r, "id")
+
+	project, err := s.store.GetProjectByID(id)
+	if err != nil {
+		if errors.Is(err, store.ErrNotFound) {
+			respondNotFound(w, "project")
+			return
+		}
+		slog.Error("failed to get project", "error", err)
+		respondError(w, http.StatusInternalServerError, "internal server error")
+		return
+	}
+
+	if s.docker == nil || project.Image == "" {
+		respondJSON(w, http.StatusOK, []any{})
+		return
+	}
+
+	images, err := s.docker.ListImagesByRef(r.Context(), project.Image)
+	if err != nil {
+		slog.Warn("list project images", "project", project.Name, "error", err)
+		respondJSON(w, http.StatusOK, []any{})
+		return
+	}
+
+	respondJSON(w, http.StatusOK, images)
+}
+
 // pruneImages handles POST /api/docker/prune-images.
 // Only removes images that belong to Docker Watcher projects (not all system images).
 func (s *Server) pruneImages(w http.ResponseWriter, r *http.Request) {

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)