feat: integrate files and portal surfaces

src/govoplan_postbox/backend/db/models.py

@@ -151,6 +151,11 @@ class PostboxTemplateRevision(Base, TimestampMixin):
         default=True,
         nullable=False,
     )
+    portal_visible: Mapped[bool] = mapped_column(
+        Boolean,
+        default=False,
+        nullable=False,
+    )
     encryption_profile: Mapped[str] = mapped_column(
         String(80),
         default="plaintext_v1",