Refactor Playlist model and add timestamps migration

Simplifies the PlaylistBase id field to a non-optional int and updates database logic to use session.refresh for id assignment. Adds Alembic migration to include created_at and updated_at columns in room_playlists for timestamp tracking.

migrations/versions/3f890a76f036_add_id_data.py

@@ -0,0 +1,39 @@
+"""add id data
+
+Revision ID: 3f890a76f036
+Revises: 8d2af11343b9
+Create Date: 2025-08-24 04:00:02.063347
+
+"""
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers, used by Alembic.
+revision: str = "3f890a76f036"
+down_revision: str | Sequence[str] | None = "8d2af11343b9"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    #op.drop_index(op.f("ix_lazer_user_achievements_achievement_id"), table_name="lazer_user_achievements")
+    #op.drop_index(op.f("uq_user_achievement"), table_name="lazer_user_achievements")
+    op.add_column("room_playlists", sa.Column("created_at", sa.DateTime(), server_default=sa.text("now()"), nullable=True))
+    op.add_column("room_playlists", sa.Column("updated_at", sa.DateTime(), server_default=sa.text("now()"), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column("room_playlists", "updated_at")
+    op.drop_column("room_playlists", "created_at")
+    op.create_index(op.f("uq_user_achievement"), "lazer_user_achievements", ["user_id", "achievement_id"], unique=True)
+    op.create_index(op.f("ix_lazer_user_achievements_achievement_id"), "lazer_user_achievements", ["achievement_id"], unique=False)
+    # ### end Alembic commands ###