Mid-game invite links and a surprise-report slip

The masthead's room code is now a button: one click copies the /join
link, which seats newcomers in a waiting room and the gallery once the
boards flip. And a 🐞 report opens a two-question slip — what happened,
what was expected — that lands in feedback.jsonl beside the rooms with
the room code, move number, round, and rules rev attached, so any
surprise can be replayed to its exact moment.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015RCWSTnb1KYTPyL4GmhGnF

packages/server/src/store.ts

@@ -148,6 +148,13 @@ export function readAllRooms(): Map<string, RoomLine[]> {
   return rooms;
 }
 
+/** Player surprise reports, one JSONL line each, beside the rooms
+ * directory — the room id and seq pin the exact moment to replay. */
+export function appendFeedback(entry: Record<string, unknown>): void {
+  ensureDataDir();
+  appendFileSync(join(DATA_DIR, "..", "feedback.jsonl"), JSON.stringify(entry) + "\n", "utf8");
+}
+
 /** Retire an abandoned room's ledger to the graveyard — never deleted,
  * only moved out of the living rooms directory. */
 export function archiveRoomFile(roomId: string): void {