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.

plugins/printedparts/migrations/versions/0002_printeditemfiles.py

@@ -0,0 +1,43 @@
+"""Add printeditemfiles: append-only print-file revisions per item.
+
+The plugin's first incremental migration on top of its 0001 baseline -
+the ADR-008 payoff: the plugin evolves its own schema without touching
+the core chain. Applied by `flask plugin upgrade-all`.
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'printedparts0002files'
+down_revision = 'printedparts0001baseline'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table(
+        'printeditemfiles',
+        sa.Column('fileid', sa.Integer(), nullable=False),
+        sa.Column('printeditemid', sa.Integer(), nullable=False),
+        sa.Column('revision', sa.Integer(), nullable=False),
+        sa.Column('filename', sa.String(length=255), nullable=False),
+        sa.Column('storedfilename', sa.String(length=191), nullable=False),
+        sa.Column('filesize', sa.Integer(), nullable=False),
+        sa.Column('uploadnote', sa.String(length=255), nullable=True),
+        sa.Column('uploadedby', sa.String(length=80), nullable=False),
+        sa.Column('createddate', sa.DateTime(), nullable=False),
+        sa.Column('modifieddate', sa.DateTime(), nullable=False),
+        sa.Column('isactive', sa.Boolean(), nullable=False),
+        sa.ForeignKeyConstraint(['printeditemid'],
+                                ['printeditems.printeditemid'],
+                                ondelete='CASCADE'),
+        sa.PrimaryKeyConstraint('fileid'),
+        sa.UniqueConstraint('storedfilename'),
+    )
+    op.create_index('ix_printeditemfiles_printeditemid',
+                    'printeditemfiles', ['printeditemid'])
+
+
+def downgrade():
+    op.drop_table('printeditemfiles')