fix: room concurrency (theoretically) (#511)

* fix: room concurrency (theoretically)

* cleanup

* cleanup

server/migrations/versions/b7df9609542c_add_unique_constraint_one_active_.py

@@ -0,0 +1,35 @@
+"""add_unique_constraint_one_active_meeting_per_room
+
+Revision ID: b7df9609542c
+Revises: d7fbb74b673b
+Create Date: 2025-07-25 16:27:06.959868
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'b7df9609542c'
+down_revision: Union[str, None] = 'd7fbb74b673b'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Create a partial unique index that ensures only one active meeting per room
+    # This works for both PostgreSQL and SQLite
+    op.create_index(
+        'idx_one_active_meeting_per_room',
+        'meeting',
+        ['room_id'],
+        unique=True,
+        postgresql_where=sa.text('is_active = true'),
+        sqlite_where=sa.text('is_active = 1')
+    )
+
+
+def downgrade() -> None:
+    op.drop_index('idx_one_active_meeting_per_room', table_name='meeting')