printedparts stage 17: gage-lab asset tag + print-files redesign

The gage lab assigns real WJRP asset numbers, so identity splits: the
internal itemcode stays auto-minted and a new optional unique
gagelabtag (migration 0003) carries the lab's number - settable on
create/edit, searchable, and resolved by the kiosk for scans and bare
keypad digits against the numeric tail of either identifier
(unique-match only). The print-files table becomes stacked revision
cards - filename with rev/current badges, one meta line, delete pinned
right - ending the horizontal scroll in that column.

plugins/printedparts/migrations/versions/0003_gagelabtag.py

@@ -0,0 +1,27 @@
+"""Add printeditems.gagelabtag: the gage-lab assigned asset tag.
+
+The gage lab issues WJRP asset numbers for printed parts; the internal
+itemcode stays auto-generated, and this optional unique tag carries the
+lab's number. The kiosk resolves scans/typed digits against both.
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'printedparts0003gagetag'
+down_revision = 'printedparts0002files'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column('printeditems',
+                  sa.Column('gagelabtag', sa.String(length=50), nullable=True))
+    op.create_index('ix_printeditems_gagelabtag', 'printeditems',
+                    ['gagelabtag'], unique=True)
+
+
+def downgrade():
+    op.drop_index('ix_printeditems_gagelabtag', table_name='printeditems')
+    op.drop_column('printeditems', 'gagelabtag')