add interactions (cheer/faves)

apps/rooms/migrations/0003_interaction.sql

@@ -0,0 +1,10 @@
+-- Per-player interaction state with a room (cheered/favorited + last visit).
+-- One row per (player, room); cheer/favorite are toggled in place.
+CREATE TABLE IF NOT EXISTS interaction (
+	player_id INTEGER NOT NULL,
+	room_id INTEGER NOT NULL,
+	cheered INTEGER NOT NULL DEFAULT 0,
+	favorited INTEGER NOT NULL DEFAULT 0,
+	last_visited_at TEXT,
+	PRIMARY KEY (player_id, room_id)
+);