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>

tests/test_editor_mobile_layers_header.py

@@ -0,0 +1,25 @@
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+GALLERY = ROOT / "static/js/galleryEditor.js"
+CSS = ROOT / "static/css/13-image-editor.css"
+
+
+def test_mobile_relocates_footer_history_into_layers_header():
+    src = GALLERY.read_text(encoding="utf-8")
+    # On phones the footer's undo/redo/history pill was floating over the layer
+    # sheet's Blend row; tuck it into the layer-sheet header instead.
+    assert "if (window.innerWidth <= 700) {" in src
+    assert "container.querySelector('.ge-footer-history')" in src
+    assert "container.querySelector('.ge-layers-header')" in src
+    assert "hdr.appendChild(fh)" in src
+
+
+def test_mobile_layers_header_pill_style():
+    css = CSS.read_text(encoding="utf-8")
+    assert ".ge-layers-header .ge-footer-history {" in css
+    idx = css.index(".ge-layers-header .ge-footer-history {")
+    block = css[idx:idx + 220]
+    assert "z-index: auto;" in block
+    assert "margin-left: auto;" in block