Initial import: shopdb-flask multi-site asset platform

Flask + Vue rewrite of the classic-ASP shopdb, built as a plugin
framework so sister GE Aerospace sites can adopt it. Product version
0.7.0-pre-0.8.0, plugin contract 0.11.0, 966 backend tests.

Key entry points:
- docs/INSTALL-WINDOWS-IIS.md - tested Windows + IIS install runbook
  (own-site and subpath deployment methods)
- docs/PILOT-DEPLOY.md - production pilot: stand up + import + verify
- docs/IMPORT-API.md - schema-agnostic legacy data import contract
- scripts/site_imports/wjf/ - West Jefferson reference import loader
- docs/adr/ - twelve accepted architecture decision records

plugins/notifications/migrations/versions/0001_notifications_anchor.py

@@ -0,0 +1,28 @@
+"""notifications plugin anchor (ownership cutover).
+
+Stamp-only no-op. The core Alembic chain (baseline .. 7d16_directoryemployees)
+already created every table this plugin owns at the cutover point, so there is
+nothing to build here. This revision gives the plugin's own chain a base that
+`flask plugin upgrade-all` can stamp into alembic_version_notifications. From this
+anchor forward, new notifications schema changes land as 000N revisions in this
+directory, never in the core chain. See ADR-008.
+"""
+from alembic import op  # noqa: F401
+import sqlalchemy as sa  # noqa: F401
+
+
+# revision identifiers, used by Alembic.
+revision = 'notifications0001anchor'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # No-op: the core chain owns every table that exists at the cutover.
+    pass
+
+
+def downgrade():
+    # No-op: this anchor never unwinds core-owned tables.
+    pass

plugins/notifications/migrations/versions/0002_index_businessunitid.py

@@ -0,0 +1,42 @@
+"""Index notifications.businessunitid (shopfloor list route filters on it).
+
+businessunitid is a soft-ref column the shopfloor feed filters by; it had no
+index. Add ix_notifications_businessunitid (matches the model's index=True).
+
+Idempotent; downgrade drops it.
+
+Revision ID: notifications0002buidx
+Revises: notifications0001anchor
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = 'notifications0002buidx'
+down_revision = 'notifications0001anchor'
+branch_labels = None
+depends_on = None
+
+_INDEX = 'ix_notifications_businessunitid'
+
+
+def _index_names(insp, table):
+    return {i['name'] for i in insp.get_indexes(table)}
+
+
+def upgrade():
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    if 'notifications' not in insp.get_table_names():
+        return
+    if _INDEX not in _index_names(insp, 'notifications'):
+        op.create_index(_INDEX, 'notifications', ['businessunitid'])
+
+
+def downgrade():
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    if 'notifications' not in insp.get_table_names():
+        return
+    if _INDEX in _index_names(insp, 'notifications'):
+        op.drop_index(_INDEX, table_name='notifications')