feat(chats): add per-user pinned chats and pinned sorting

alembic/versions/0015_chat_pin_fields.py

@@ -0,0 +1,28 @@
+"""add chat pin fields to chat user settings
+
+Revision ID: 0015_chat_pin_set
+Revises: 0014_chat_user_set
+Create Date: 2026-03-08 19:20:00.000000
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = "0015_chat_pin_set"
+down_revision: Union[str, Sequence[str], None] = "0014_chat_user_set"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column("chat_user_settings", sa.Column("pinned", sa.Boolean(), nullable=False, server_default=sa.text("false")))
+    op.add_column("chat_user_settings", sa.Column("pinned_at", sa.DateTime(timezone=True), nullable=True))
+
+
+def downgrade() -> None:
+    op.drop_column("chat_user_settings", "pinned_at")
+    op.drop_column("chat_user_settings", "pinned")
+