perf(db): index activity_events by (event_type, created_at)

backend/migrations/versions/b05c7b628636_add_activity_events_event_type_created_.py

@@ -0,0 +1,32 @@
+"""add activity_events event_type created_at index
+
+Revision ID: b05c7b628636
+Revises: bbd5bbb26d97
+Create Date: 2026-02-12 09:54:32.359256
+
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'b05c7b628636'
+down_revision = 'bbd5bbb26d97'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # Speed activity feed/event filters that select by event_type and order by created_at.
+    # Allows index scans (often backward) with LIMIT instead of bitmap+sort.
+    op.create_index(
+        "ix_activity_events_event_type_created_at",
+        "activity_events",
+        ["event_type", "created_at"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_activity_events_event_type_created_at", table_name="activity_events")

backend/migrations/versions/bbd5bbb26d97_merge_heads.py

@@ -0,0 +1,26 @@
+"""merge heads
+
+Revision ID: bbd5bbb26d97
+Revises: 99cd6df95f85, b4338be78eec
+Create Date: 2026-02-12 09:54:21.149702
+
+"""
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'bbd5bbb26d97'
+down_revision = ('99cd6df95f85', 'b4338be78eec')
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    pass
+
+
+def downgrade() -> None:
+    pass