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/knowledgebase/models/knowledgebase.py

@@ -0,0 +1,40 @@
+"""Knowledge Base model.
+
+Non-asset plugin model. The `knowledgebase` table lives in the core Alembic
+chain (bundled-plugin schema is folded into core, ADR-004); this class just
+maps it and is registered via the plugin's get_models hook. The appid FK
+references the core applications table by name, which resolves at mapper config
+time without importing the core model.
+"""
+
+from datetime import datetime, timezone
+
+from shopdb.api import db, BaseModel
+
+
+def _utcnow():
+    # naive UTC to match the other DB DateTime columns (stored without tzinfo)
+    return datetime.now(timezone.utc).replace(tzinfo=None)
+
+
+class KnowledgeBase(BaseModel):
+    """Knowledge Base article linking to external resources."""
+    __tablename__ = 'knowledgebase'
+
+    linkid = db.Column(db.Integer, primary_key=True)
+    appid = db.Column(db.Integer, db.ForeignKey('applications.appid'))
+    shortdescription = db.Column(db.String(500), nullable=False)
+    linkurl = db.Column(db.String(2000))
+    keywords = db.Column(db.String(500))
+    clicks = db.Column(db.Integer, default=0)
+    lastupdated = db.Column(db.DateTime, default=_utcnow, onupdate=_utcnow)
+
+    # Relationship to the core Application model (resolved by class name).
+    application = db.relationship('Application', backref=db.backref('knowledgebase_articles', lazy='dynamic'))
+
+    def __repr__(self):
+        return f"<KnowledgeBase {self.linkid}: {self.shortdescription[:50] if self.shortdescription else 'No desc'}>"
+
+    def increment_clicks(self):
+        """Increment click counter."""
+        self.clicks = (self.clicks or 0) + 1