chore: v2.8.67 — remove user chat and drop its data

The chat_* tables are dropped at start, and <data dir>/chat/ (its uploads)
is deleted.

server/db.js

@@ -1854,6 +1854,22 @@ try {
   db.prepare("ALTER TABLE dashboard_runs ADD COLUMN chat_token_hash TEXT").run();
 }
 
+// v2.8.65–2.8.66 shipped a chat between users (chat_* tables, uploads under
+// <data dir>/chat/); it was removed in v2.8.67, and its data goes with it.
+try {
+  db.exec(`
+    DROP TABLE IF EXISTS chat_files;
+    DROP TABLE IF EXISTS chat_messages;
+    DROP TABLE IF EXISTS chat_members;
+    DROP TABLE IF EXISTS chat_rooms;
+  `);
+  if (!process.env.DASHBOARD_DB_PATH) {
+    fs.rmSync(path.join(getDataDir(), "chat"), { recursive: true, force: true });
+  }
+} catch {
+  /* best effort: a leftover is unused */
+}
+
 // Server mode: whose browser a push subscription is (`users.id`); NULL in
 // local mode. A user's notifications go only to their own subscriptions.
 try {