feat(api): add GET /api/items/by-uuid/{uuid} endpoint

Closes #43

Adds a new read-only endpoint to resolve a Silo item UUID to its full
ItemResponse. Used by silo-mod to resolve FreeCAD document SiloUUID
properties to part numbers during BOM sync.

- Reuses existing ItemRepository.GetByID() (items.id is the stable UUID)
- Returns 404 for archived items
- Registered in viewer-accessible route group (no editor role required)

internal/api/handlers.go

@@ -465,6 +465,26 @@ func (s *Server) HandleCreateItem(w http.ResponseWriter, r *http.Request) {
 	s.broker.Publish("item.created", mustMarshal(resp))
 }
 
+// HandleGetItemByUUID retrieves an item by its stable UUID (the items.id column).
+// Used by silo-mod to resolve FreeCAD document SiloUUID properties to part numbers.
+func (s *Server) HandleGetItemByUUID(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	uuid := chi.URLParam(r, "uuid")
+
+	item, err := s.items.GetByID(ctx, uuid)
+	if err != nil {
+		s.logger.Error().Err(err).Msg("failed to get item by UUID")
+		writeError(w, http.StatusInternalServerError, "internal_error", "Failed to get item")
+		return
+	}
+	if item == nil || item.ArchivedAt != nil {
+		writeError(w, http.StatusNotFound, "not_found", "Item not found")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, itemToResponse(item))
+}
+
 // HandleGetItem retrieves an item by part number.
 // Supports query param: ?include=properties to include current revision properties.
 func (s *Server) HandleGetItem(w http.ResponseWriter, r *http.Request) {

internal/api/routes.go

@@ -119,6 +119,7 @@ func NewRouter(server *Server, logger zerolog.Logger) http.Handler {
 		r.Route("/items", func(r chi.Router) {
 			r.Get("/", server.HandleListItems)
 			r.Get("/search", server.HandleFuzzySearch)
+			r.Get("/by-uuid/{uuid}", server.HandleGetItemByUUID)
 			r.Get("/export.csv", server.HandleExportCSV)
 			r.Get("/template.csv", server.HandleCSVTemplate)
 			r.Get("/export.ods", server.HandleExportODS)