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

shopdb/plugins/templates/plugin.py.tmpl

@@ -0,0 +1,70 @@
+"""$Name plugin main class.
+
+$description
+"""
+
+import json
+import logging
+from pathlib import Path
+from typing import List, Dict, Optional, Type
+
+from flask import Flask, Blueprint
+
+from shopdb.plugins.base import BasePlugin, PluginMeta
+from shopdb.api import db, AssetType
+
+from .models import $Name
+from .api import ${name}_bp
+
+logger = logging.getLogger(__name__)
+
+
+class ${Name}Plugin(BasePlugin):
+    """$Name plugin.
+
+    $description
+    """
+
+    def __init__(self):
+        manifest_path = Path(__file__).parent / 'manifest.json'
+        with open(manifest_path) as f:
+            self._manifest = json.load(f)
+
+    @property
+    def meta(self) -> PluginMeta:
+        return PluginMeta(
+            name=self._manifest['name'],
+            version=self._manifest['version'],
+            description=self._manifest['description'],
+            author=self._manifest.get('author', ''),
+            dependencies=self._manifest.get('dependencies', []),
+            core_version=self._manifest.get('core_version', '>=0.1.0'),
+            api_prefix=self._manifest.get('api_prefix'),
+        )
+
+    def get_blueprint(self) -> Optional[Blueprint]:
+        return ${name}_bp
+
+    def get_models(self) -> List[Type]:
+        return [$Name]
+
+    def init_app(self, app: Flask, db_instance) -> None:
+        logger.info(f'$Name plugin initialized (v{self.meta.version})')
+
+    def on_install(self, app: Flask) -> None:
+        with app.app_context():
+            self._ensure_asset_type()
+            logger.info('$Name plugin installed')
+
+    def _ensure_asset_type(self) -> None:
+        existing = AssetType.query.filter_by(assettype='$name').first()
+        if not existing:
+            asset_type = AssetType(
+                assettype='$name',
+                pluginname='$name',
+                tablename='$name',
+                description=self.meta.description,
+            )
+            db.session.add(asset_type)
+            db.session.commit()
+            logger.debug('Created asset type: $name')