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/api/__init__.py

@@ -44,6 +44,8 @@ from shopdb.core.models import (
     OperatingSystem,
     AssetRelationship,
     RelationshipType,
+    User,
+    Role,
 )
 
 # Response + pagination helpers for plugin API blueprints
@@ -78,6 +80,7 @@ from shopdb.core.services.dualpath import (
 
 # Legacy employee directory lookup (read-only) used by notifications
 from shopdb.utils.employee_db import employee_connection
+from shopdb.utils.mailer import send_email, send_alert
 
 # CMMC USB check-in/out database (read-write) used by the usb plugin
 from shopdb.utils.cmmc_usb_db import cmmc_usb_connection
@@ -266,6 +269,10 @@ __all__ = [
     'parse_import_datetime',
     # Legacy employee directory
     'employee_connection',
+    'send_email',
+    'send_alert',
+    'User',
+    'Role',
     # CMMC USB check-in/out database
     'cmmc_usb_connection',
 ]