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/README.md

@@ -0,0 +1,24 @@
+# scripts/migration (superseded)
+
+The direct-SQL migrators that used to live here (`migrate_assets.py`,
+`migrate_communications.py`, `migrate_notifications.py`, `migrate_usb.py`,
+`run_migration.py`, `verify_migration.py`) and `scripts/import_from_mysql.py`
+were **removed** - they had drifted badly out of sync with the current schema
+(they targeted a nonexistent `equipment` table, the retired `Machine` model, and
+columns that no longer exist) and were actively misleading.
+
+## Use the import API + a site loader instead
+
+Legacy data is imported through the maintained, schema-agnostic contract in
+the IMPORT-API page in the project wiki (create through real endpoints
+with an admin PAT + `X-Import-Mode`). Each adopting site writes a thin loader
+that reads its own source database and drives that API.
+
+- Reference implementation: [`scripts/site_imports/wjf/`](../site_imports/wjf/)
+  (West Jefferson classic-ASP -> flask).
+- Adoption playbook: the IMPORT-ADOPTION page in the project wiki.
+
+## What's kept here
+
+- `fix_legacy_schema.sql` - one-time SQL fixups against a legacy source DB.
+- `one-offs/` - individual one-shot SQL snippets (see its README).