Product text import from agency XLSX workbooks

VITEC Import module: Products tab is now a searchable/sortable product
overview. "Edit Product" opens an XLSX upload with per-field source
mapping (component + cell), old/new preview and checkbox apply via
DataHandler; the mapping and manual matches are persisted and preselect
the next workbook. Category workbooks are detected and rejected.

- new: ProductXlsxReader (PhpSpreadsheet), ProductTextImportController,
  Products/ProductTexts templates, 4 module routes
- related products: per-pair card text in new side table
  tx_vitec_product_related_text (survives MM rewrites), emitted as
  `cardtext` in the product JSON; missing MM relations added add-only
- card copy read from Body Copy (D) with fallback to CTA/Card Copy (E) -
  the workbooks fill either depending on row type
- product detail page <title> now uses seotitle with title fallback
  (provider made singleton and fed from the JSON renderer)
- per-user recent-search badges; last loaded workbook stored per product
  (tx_vitec_product_workbook), Edit Product reopens on it
- composer: add phpoffice/phpspreadsheet ^5.9
- diagnostics: migrations/check_workbook.php

composer.json

@@ -22,6 +22,7 @@
 		"friendsoftypo3/headless": "^5.0@rc",
 		"georgringer/news": "^14.0",
 		"netzbewegung/nb-headless-content-blocks": "^0.0.23",
+		"phpoffice/phpspreadsheet": "^5.9",
 		"plan2net/backend-category-hierarchy": "^14.0",
 		"typo3/cms-backend": "^14.3",
 		"typo3/cms-belog": "^14.3",