Jul 10 - Update facility's area with QR code

app/models/facility.py

@@ -50,9 +50,26 @@ class Area(db.Model):
     name = db.Column(db.String(255), nullable=False)
     area_type = db.Column(db.String(50))
 
+    # Phase 39: unguessable token encoded in the area's public QR code.
+    # The QR points at /f/area/<public_token>, a login-free occupant summary
+    # page scoped to this area. Backfilled for existing rows by phase39.
+    public_token = db.Column(db.String(48), nullable=True, unique=True, index=True)
+
     # Relationships
     inspections = db.relationship('Inspection', backref='area', lazy='dynamic')
     issues = db.relationship('Issue', backref='area', lazy='dynamic')
 
+    @staticmethod
+    def generate_public_token() -> str:
+        """Return a fresh URL-safe token for the public QR link."""
+        return secrets.token_urlsafe(24)
+
+    def ensure_public_token(self) -> str:
+        """Return this area's public_token, generating & persisting one if it
+        is missing. The caller is responsible for db.session.commit()."""
+        if not self.public_token:
+            self.public_token = self.generate_public_token()
+        return self.public_token
+
     def __repr__(self):
         return f'<Area {self.name}>'