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_psd_js.py

@@ -0,0 +1,39 @@
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def read(rel):
+    return (ROOT / rel).read_text(encoding="utf-8")
+
+
+PSD = read("static/js/editor/psd.js")
+EXPORT = read("static/js/editor/export-dialog.js")
+IMPORT = read("static/js/editor/wire-import.js")
+SW = read("static/sw.js")
+
+
+def test_psd_module_exports():
+    assert "export function exportPsd(" in PSD
+    assert "export function parsePsd(" in PSD
+    assert "export function packBits(" in PSD
+    assert "export function unpackBits(" in PSD
+    assert "8BPS" in PSD
+    assert "const psb = version === 2;" in PSD
+
+
+def test_export_dialog_offers_psd():
+    assert "from './psd.js';" in EXPORT
+    assert "exportPsd(" in EXPORT
+    assert "psd:" in EXPORT
+    assert 'data-format="psd"' in EXPORT
+
+
+def test_import_handles_psd():
+    assert "from './psd.js';" in IMPORT
+    assert "parsePsd(" in IMPORT
+    assert ".psd" in IMPORT
+
+
+def test_psd_module_is_precached():
+    assert "/static/js/editor/psd.js" in SW