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_layer_opacity_footer.py

@@ -0,0 +1,31 @@
+import re
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+CSS = (ROOT / "static" / "css" / "13-image-editor.css").read_text()
+SW = (ROOT / "static" / "sw.js").read_text()
+
+
+def test_idle_layer_rows_hide_the_opacity_slider():
+    assert ".ge-layer-item:not(.ge-adj-sub-item):not(.ge-mask-sub-item) > .ge-layer-opacity-row {\n    display: none;" in CSS
+    assert ".ge-layer-item:not(.ge-adj-sub-item):not(.ge-mask-sub-item).active > .ge-layer-opacity-row {\n    display: flex;" in CSS
+
+
+def test_layer_opacity_slider_is_thin_and_not_full_width():
+    assert "body.ge-editor-open .ge-layer-item .ge-layer-opacity {" in CSS
+    assert "min-height: 0 !important;" in CSS
+    assert "width: 140px !important;" in CSS
+
+
+def test_layers_footer_stays_on_one_row():
+    idx = CSS.rindex(".ge-layers-footer {")
+    block = CSS[idx:idx + 400]
+    assert "flex-wrap: nowrap;" in block
+    assert ".ge-layers-footer #ge-layer-fill {" in CSS
+
+
+def test_sw_cache_bumped():
+    # Version-agnostic: every commit bumps the SW cache, so pinning the exact
+    # number makes this test fail on the next commit.
+    m = re.search(r"CACHE_NAME = 'odysseus-v\d+-pr40-editor-precache'", SW)
+    assert m, "CACHE_NAME not found"