feat(photo-editor): Ajax Image Editor client (Photoshop-parity tools)

Photoshop-parity editor client: layers, selection/masking, brushes,
smart filters, LUT import, Quick Edit, mobile gestures, workspaces,
batch operations, and the service-worker versioning (v978->v1006).

Source: vendor/photocraft (ad1cff44) photo-editor client files, merged
onto upstream/dev (a8c147b2). Conflict resolution documented in
pr_work/A_conflicts.md; editor files taken from vendor/photocraft
(upstream's editor is an earlier snapshot of the same feature).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

static/js/editor/tools/object-select.js

@@ -0,0 +1,88 @@
+// Object Selection brush — drag a rough box over the subject and let the
+// server-side segmentation model (SAM, via /api/image/mask) pick it out.
+// The stroke is sampled into positive/negative points plus a bounding
+// box, both already supported by the backend endpoint.
+
+import { selectionModeForEvent } from '../selection-modifiers.js';
+
+export function createObjectSelectTool({
+  activeLayer,
+  saveState,
+  requestSam,
+  canvasCoords,
+  layerOffset,
+  showToast,
+  syncToolClearIndicators,
+}) {
+  let active = false;
+  let layer = null;
+  let points = [];
+  let box = null;
+  let mode = 'replace';
+
+  const addPoint = (coords, event) => {
+    if (!layer) return;
+    const off = layerOffset(layer) || { x: 0, y: 0 };
+    const lx = Math.floor(coords.x - off.x);
+    const ly = Math.floor(coords.y - off.y);
+    if (lx < 0 || ly < 0 || lx >= layer.canvas.width || ly >= layer.canvas.height) return;
+    const last = points[points.length - 1];
+    if (last && Math.hypot(lx - last.x, ly - last.y) < 8) return;
+    points.push({ x: lx, y: ly, label: event.altKey ? 0 : 1 });
+    if (!box) box = [lx, ly, lx, ly];
+    else {
+      box[0] = Math.min(box[0], lx);
+      box[1] = Math.min(box[1], ly);
+      box[2] = Math.max(box[2], lx);
+      box[3] = Math.max(box[3], ly);
+    }
+  };
+
+  const begin = (event) => {
+    layer = activeLayer();
+    if (!layer) {
+      showToast?.('Select a layer');
+      return;
+    }
+    active = true;
+    points = [];
+    box = null;
+    mode = selectionModeForEvent(event, 'replace');
+    const coords = canvasCoords(event);
+    if (coords) addPoint(coords, event);
+  };
+
+  const drag = (event) => {
+    if (!active) return;
+    const coords = canvasCoords(event);
+    if (coords) addPoint(coords, event);
+  };
+
+  const end = async () => {
+    if (!active) return;
+    active = false;
+    const target = layer;
+    const pts = points;
+    const bx = points.length ? box : null;
+    points = [];
+    box = null;
+    layer = null;
+    if (!target || !pts.length) return;
+    saveState();
+    try {
+      await requestSam(target, { points: pts, box: bx }, mode);
+    } catch (err) {
+      if (err?.name !== 'AbortError') showToast?.('Object selection failed');
+    }
+    syncToolClearIndicators?.();
+  };
+
+  const cancel = () => {
+    active = false;
+    points = [];
+    box = null;
+    layer = null;
+  };
+
+  return { begin, drag, end, cancel };
+}