printedparts stage 14: retire/restore in the UI, dashless item codes

Retire button with confirmation on the detail page (item leaves the
storefront and the kiosk rejects its code; ledger history and label
survive), Restore on retired items, and an Include-retired list toggle
with a badge. Restore is its own permission-gated POST - the generic
update still cannot flip isactive. New codes mint as WJRP0042 style
without the dash; existing codes are immutable bin labels and keep
their form.

frontend/src/views/settings/PrintedPartsSettings.vue

@@ -13,7 +13,7 @@
         <input v-model="values.printedparts_code_prefix" type="text"
                class="form-control" maxlength="8" />
         <p class="field-hint">
-          New items mint codes like {{ values.printedparts_code_prefix || '3DP' }}-0042.
+          New items mint codes like {{ values.printedparts_code_prefix || '3DP' }}0042.
           Changing it does not rename existing items.
         </p>
       </div>