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/tool-shortcuts.js

@@ -4,4 +4,5 @@ export const TOOL_SHORTCUTS = Object.freeze({
   brush: 'B', gradient: 'G', eraser: 'E', eyedropper: 'I',
   smudge: 'Y', clone: 'S', heal: 'J', dodge: 'O',
   marquee: 'M', lasso: 'L', wand: 'W', pen: 'P',
+  zoom: 'Z',
 });