- ApiClient: add getSuppliers, addSupplier, updateSupplier,
orderSuppliers, deleteSupplier on article namespace
- api/index.js: expose same methods in legacy http client
- StorageManager: add #supplierWatchers Map and watchArticleSuppliers()
backed by article-<sku> SSE signal; wired up as article.supplierWatch
- ArticleTileTab: pass article prop to ArticleSupplierTab
- ArticleSupplierDialog (new): dialog to assign / edit a supplier link
(supplier autocomplete, Lief.-SKU, VPE, stock, EK Netto + MwSt.)
- ArticleSupplierTab: full supplier management table with reordering
(up/down arrows → PUT /supplier/order), inline edit and delete,
stock badge, purchase price display and empty state
Add number & setting API endpoints, StorageManager caches, and a Settings
dialog (tabs for settings keys and number ranges) reachable from the user
menu. Show Kundennummer and creation date in the Kunde list, and refactor
Neuer Kunde to show an auto-generated number with group select.
