fix: enable resize/rotate controls on single-click object selection

In setMode('select'), explicitly set hasControls, hasBorders, and evented
on all objects. In drawing modes, disable selectable/evented to prevent
accidental interaction. Fixes controls only appearing on multi-select drag.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

client/static/js/annotation-editor.js

@@ -526,12 +526,19 @@ function annotationEditor() {
         this.canvas.defaultCursor = 'default';
         this.canvas.forEachObject(function (o) {
           o.selectable = true;
+          o.evented = true;
+          o.hasControls = true;
+          o.hasBorders = true;
         });
       } else {
-        // marker, arrow, rect
+        // marker, arrow, rect — disable object interaction during drawing
         this.canvas.selection = false;
         this.canvas.defaultCursor = 'crosshair';
         this.canvas.discardActiveObject();
+        this.canvas.forEachObject(function (o) {
+          o.selectable = false;
+          o.evented = false;
+        });
       }
 
       this.canvas.renderAll();