feat(new-layout): add-to-cart handler + piece configurator (Phase 02 plans 01-02)

Plan 02-01 (piece/crop configurator, complete):
- #piece reuse z shared partial product-cover-thumbnails.tpl
- 8 hidden inputs (is_crop, crop_pos_x/y, crop_width/height, piece_bg_top/left, is_reflection) w formie #add-to-cart-or-refresh
- Defensive setup w custom.js: setTimeout(600) init, no-op override totalpriceinfospecific/prod, DOM stubs
- CSS scope pod body#product .product-size-data .product-size-data--new

Plan 02-02 (add-to-cart submission, PARTIAL):
- Capture-phase native addEventListener (useCapture=true) blokuje PS core crash
  (button poza formą w nowym layoucie — closest('form') zwracało 0)
- Manualny AJAX POST: form.serialize() + qty + add=1&action=update do /pl/koszyk
- Fancybox-blocker port z custom.js:327 (nie odpalał się bo selector 0 matches)
- Manual sync is_crop/crop_width/height przed POST (obejście crash checkedHandler)
- prestashop.emit('updatedCart') + defensive blockcart refresh fetch
- Loading spinner + success flash CSS
- Inline handler mirror w product.tpl z idempotency guard (window.__p02p02Bound)
  — cache-buster dla browser cachowanego custom.js

Deferred do Plan 02-03 (customization + modal blocker dla production):
- Customization nie zapisuje się (squaremeter hook gate'owany discretion=on + brak dimension fields)
- Success modal (wymaga POST do /module/ps_shoppingcart/ajax)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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