printedparts stage 2: models, real 0001 baseline, tables live

PrintedItem (catalog: code, name, image, cached quantityonhand,
per-item threshold, bin) and PrintedItemTransaction (the ledger:
signed quantity change attributed to a badge-resolved employee).
Both registered in PLUGIN_TABLE_OWNERS; 0001 is a post-cutover real
baseline. The migration-guard test learns the new expected head.
Routes are a placeholder ping until the next stage - the scaffold's
list route imported the deleted scaffold model, which surfaces as an
empty 'Migration error' because the alembic env imports the models
package.

plugins/printedparts/plugin.py

@@ -16,7 +16,7 @@ from flask import Flask, Blueprint
 from shopdb.plugins.base import BasePlugin, PluginMeta
 from shopdb.api import db, Setting
 
-from .models import Printedparts
+from .models import PrintedItem, PrintedItemTransaction
 from .api import printedparts_bp
 
 logger = logging.getLogger(__name__)
@@ -46,7 +46,7 @@ class PrintedpartsPlugin(BasePlugin):
         return printedparts_bp
 
     def get_models(self) -> List[Type]:
-        return [Printedparts]
+        return [PrintedItem, PrintedItemTransaction]
 
     def init_app(self, app: Flask, db_instance) -> None:
         logger.info(f'Printedparts plugin initialized (v{self.meta.version})')