Add the printedparts plugin: 3D-printed parts storefront and kiosk

Catalog with photos and append-only print-file revisions, a stock
ledger attributing every take/restock/adjust to a badge-resolved
employee, a touch kiosk (scan bin, scan badge, keypad quantity) with a
deliberately open decrement-only take endpoint, 1x0.5in CODE128 bin
labels, low-stock email alerts to selected users, roles, or addresses,
and stock/consumption/by-person reports with a cache-vs-ledger
reconcile. Ships disabled; enable per site. Contract 0.13.0 adds the
mailer and the User/Role models to the plugin surface.

shopdb/plugins/alembic_template.py

@@ -53,6 +53,8 @@ PLUGIN_TABLE_OWNERS: dict[str, Iterable[str]] = {
     'measuringtools': ('measuringtooltypes', 'measuringtools'),
     'network':       ('networkdevicetypes', 'networkdevices', 'vlans', 'subnets'),
     'notifications': ('notificationtypes', 'notifications'),
+    'printedparts':  ('printeditems', 'printeditemtransactions',
+                      'printeditemfiles'),
     'printers':      ('printertypes', 'printers', 'modelsupplies', 'printerdrivers'),
     'slides':        ('tvslides',),
     'usb':           ('usbdevicetypes', 'usbdevices', 'usbcheckouts'),