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

scripts/migration/one-offs/README.md

@@ -0,0 +1,16 @@
+# One-off migration scripts (historical)
+
+These are hand-run SQL scripts kept for reference. They are NOT part of the
+Alembic chain (`migrations/versions/`) and are not run by `flask db upgrade`. A
+fresh install never needs them; they exist for databases that predate the
+corresponding change.
+
+- `add_recertification_type.sql` - inserts the blue "Recertification"
+  notification type into an already-existing database. Historical: the
+  notifications plugin now seeds this type on install
+  (`plugins/notifications/plugin.py`), so any fresh install already has it. Only
+  a pre-existing DB that was never re-installed needs this script. Idempotent.
+
+A related one-off, widening `notifications.employeesso` / `employeename` to
+TEXT, has been removed because it is fully superseded by Alembic migration
+`7d02_widen_notification_employee_cols`.