fix(migration): simplify aisle migration + add persistent backup script

- Drop the empty batch_alter_table block and the meaningless
  set_config call from migration 0015. Temp tables still persist
  for the migration's session (Alembic's transactional_ddl).
- New backend/scripts/persist_aisle_backup.sql creates
  public.ingredient_aisle_backup_0015 and
  public.grocery_item_aisle_backup_0015 permanent tables for
  operators who want a recoverable record beyond the migration.
- Update Review/sprint2-verification.md, Review/ui-nielsen-audit.md
  and fix-ui-audit.md with the correct container-based deploy
  steps: docker compose exec db psql -U mealplanner -d mealplanner
  -f /dev/stdin < ...sql. Host psql is not available on the
  deployment host; the db runs inside the container.

backend/alembic/versions/0015_normalize_pantry_aisles.py

@@ -3,10 +3,28 @@
 Revision ID: 0015
 Revises: 0014
 Create Date: 2026-06-02
+
+Normalizes free-text aisle values on `ingredient.aisle` and `grocery_item.aisle`
+to a fixed canonical set. Runs in a single transaction (Alembic default); both
+op.execute calls share the same session, so the temp backup tables persist
+for the duration of the upgrade.
+
+Backup tables: the temp tables `ingredient_aisle_backup` and
+`grocery_item_aisle_backup` are created for the migration's session. They
+auto-drop when the session ends. If you need a persistent backup, run
+`backend/scripts/persist_aisle_backup.sql` BEFORE this migration.
+
+Deploy via Docker (the db runs inside a container; no host psql required):
+
+    # 1. dry-run preview:
+    docker compose exec db psql -U mealplanner -d mealplanner \\
+        -f /dev/stdin < backend/scripts/dry_run_aisle_migration.sql
+
+    # 2. apply:
+    docker compose exec backend alembic upgrade head
 """
 from typing import Sequence, Union
 
-import sqlalchemy as sa
 from alembic import op
 
 # revision identifiers, used by Alembic.
@@ -16,20 +34,6 @@ branch_labels: Union[Sequence[str], None] = None
 depends_on: Union[Sequence[str], None] = None
 
 
-CANONICAL_AISLES = (
-    "Produce",
-    "Meat & Seafood",
-    "Dairy & Eggs",
-    "Pantry",
-    "Frozen",
-    "Bakery",
-    "Beverages",
-    "Spices",
-    "Other",
-)
-
-# Map from lowercased source value to canonical label. Keep the rule
-# order narrow -> broad; longest matches win via SQL CASE.
 NORMALIZATION_RULES = [
     ("canned goods", "Pantry"),
     ("canned", "Pantry"),
@@ -78,23 +82,15 @@ def _normalize(table: str) -> None:
 
 
 def upgrade() -> None:
-    bind = op.get_bind()
-    with op.batch_alter_table("ingredient") as batch:
-        pass
     _normalize("ingredient")
     _normalize("grocery_item")
-    bind.execute(
-        sa.text(
-            "SELECT set_config('app.aisle_backup_retention', 'aisle_migration_0015', false)"
-        )
-    )
 
 
 def downgrade() -> None:
-    # Best-effort downgrade: the backup temp tables only exist within the
-    # upgrade transaction. Restoring the pre-normalization state is not
-    # possible from this migration alone. Operators must restore from a
-    # database snapshot taken before upgrade.
+    # The temp backup tables only exist for the migration's session.
+    # Restoring the pre-normalization state is not possible from this
+    # migration alone. Operators must restore from a database snapshot
+    # taken before upgrade.
     raise NotImplementedError(
         "Cannot reverse aisle normalization without an external backup. "
         "Restore the database from a snapshot taken before 0015 was applied."