Security hardening, multi-site portability, and a documentation and API-surface sweep

shopdb/plugins/alembic_template.py

@@ -180,3 +180,15 @@ def run_migrations():
             )
             with context.begin_transaction():
                 context.run_migrations()
+            # SAME FIX AS migrations/env.py. MySQL DDL commits implicitly, which
+            # flushes everything queued before it - including the PREVIOUS
+            # migration's version stamp. The LAST migration of a run has no DDL
+            # after it, so its stamp is rolled back when the connection closes:
+            # the schema change survives, alembic_version stays one revision
+            # behind, and `flask plugin upgrade-all` exits 0 having silently
+            # re-run that migration - again on every deploy after.
+            #
+            # Core got this fix; the per-plugin chains run through THIS file and
+            # did not, so every plugin head has been re-running on MySQL. That is
+            # only invisible while every head happens to be idempotent.
+            connection.commit()