feat(agents): Update task comment requirements and add in_progress_at tracking

backend/alembic/versions/c1a2b3c4d5e7_add_task_in_progress_at.py

@@ -0,0 +1,31 @@
+"""add task in_progress_at
+
+Revision ID: c1a2b3c4d5e7
+Revises: b9d22e2a4d50
+Create Date: 2026-02-04 13:34:25.000000
+
+"""
+from __future__ import annotations
+
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision = "c1a2b3c4d5e7"
+down_revision = "b9d22e2a4d50"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.execute(
+        "ALTER TABLE tasks ADD COLUMN IF NOT EXISTS in_progress_at TIMESTAMP WITHOUT TIME ZONE"
+    )
+    op.execute(
+        "CREATE INDEX IF NOT EXISTS ix_tasks_in_progress_at ON tasks (in_progress_at)"
+    )
+
+
+def downgrade() -> None:
+    op.execute("DROP INDEX IF EXISTS ix_tasks_in_progress_at")
+    op.execute("ALTER TABLE tasks DROP COLUMN IF EXISTS in_progress_at")