a turn hands back its trace id, and one wire op corrects it (V-630)

The correction is the only supervised signal in the box, so the cost of
giving one has to be near zero. That means the surface needs the trace id of
the turn it is showing, which it had no way to learn: handleText returns one
string and the trace was written after the reply left.

The id rides back on ChatReply through the same context sink querySource
uses, so the mic, telegram and the web keep the one signature they share.
CorrectTurn takes a trace id and an optional target, which is deliberately
reach-agnostic: nothing about it assumes a browser.

store.ErrNoSuchTrace gets a wire twin. A turn past the retention bound is
gone, and that is the expected outcome of correcting an old turn, not a
broken database.

cmd/mavend/tick_api.go

@@ -97,10 +97,19 @@ func (d *daemonAPI) Chat(ctx context.Context, conversation, text string) (ipc.Ch
 		return ipc.ChatReply{}, errors.New("mavend: chat not available")
 	}
 	ctx, sink := withQuerySourceSink(ctx)
+	// The trace id rides back the same way (V-630), so /chat can offer a
+	// correction on the turn it is already showing. 0 when nothing persisted.
+	ctx, traces := withTraceIDSink(ctx)
 	reply := d.chatFn(ctx, conversation, text)
-	return ipc.ChatReply{Reply: reply, Source: sink.Name()}, nil
+	return ipc.ChatReply{Reply: reply, Source: sink.Name(), TraceID: traces.ID()}, nil
 }
 
+// CorrectTurn is NOT overridden here, and that is deliberate (V-630). Every other
+// diagnostic on this type exists because the daemon holds something the store
+// cannot answer from a table. A correction is a table, so the embedded store
+// adapter is already the right answer and a second implementation here would be
+// a second place for it to drift.
+
 // MCPServers — the configured MCP servers and their health (Vikunja #251).
 // Empty, not an error, when the mcp block is absent: "not configured" is the
 // default state and the web surface renders it as such.