A rewound turn's id is forgotten, so sending it again runs the turn anew

The turn log answered a repeated id with what that turn had answered, which
was right for a prompt sent twice over a dropped link and wrong for a turn
the web UI had just rewound to edit: the same id came back with the old
reply. rewind now returns the ids it took out, both handlers forget them from
the log, and the turn file drops them too, or the next load would have
brought them back.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/session/store.ts

@@ -123,10 +123,11 @@ export class Store {
     return rows.find((r) => (JSON.parse(r.json) as Message).role === "user" && (JSON.parse(r.json) as { turnId?: string }).turnId === turnId)?.id
   }
 
-  /** How many turns start at row `fromId` or after it: the visible user messages that carry a turn id. */
-  turnsFrom(sessionId: string, fromId: number): number {
-    const rows = this.db.query("SELECT json FROM messages WHERE session_id = ? AND role = 'user' AND kind = 'message' AND id >= ?").all(sessionId, fromId) as { json: string }[]
-    return rows.filter((r) => typeof (JSON.parse(r.json) as { turnId?: string }).turnId === "string").length
+  /** The turns that start at row `fromId` or after it, oldest first: the ids the visible user
+   *  messages carry. */
+  turnIdsFrom(sessionId: string, fromId: number): string[] {
+    const rows = this.db.query("SELECT json FROM messages WHERE session_id = ? AND role = 'user' AND kind = 'message' AND id >= ? ORDER BY id").all(sessionId, fromId) as { json: string }[]
+    return rows.map((r) => (JSON.parse(r.json) as { turnId?: string }).turnId).filter((id): id is string => typeof id === "string")
   }
 
   /** Record a compaction: what the model sees from here on starts with this summary. */