Draw a peer message above the turn it started, not below it

The live Claude Code path only learns a turn was another agent's when
the turn ends -- the whole of the message arrives as an `origin` object
on the `result` -- so the note was appended after everything it caused,
and the transcript showed the answer above the question.

It cannot be recorded in place: by the time anyone knows, the reply is
already written, and the transcript is append-only. So the event carries
where it belongs instead. `PeerMessage` gains `turnStart`, the seq of
the status that opened its turn, stamped by the pump -- the only thing
that knows a seq and the only thing that sees every driver's turns. The
phone gives the note that seq, so it sorts into place rather than being
drawn out of order at the end. A status draws no row, so there is
nothing for it to collide with and the list stays sorted, which the
scroll anchor and paging both depend on.

Absent where there is nothing to correct: a message replayed out of a
session file by `import` is already in the right place, and one that
opened no turn has no turn to sit above. Both stay where they arrive.

The echo driver gets `/peer-turn` for the live shape, beside `/peer` for
the in-place one. Verified on the emulator both ways, live and on
replay, plus an ordinary `/tools` turn to confirm the run grouping the
insertion cuts through is unaffected.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

server/src/session/driver.rs

@@ -225,6 +225,24 @@ pub enum Event {
         /// recognises it by -- the socket path it came from is not.
         from: String,
         text: String,
+        /// The seq of the `Status::Running` that opened the turn this
+        /// message started, so a reader can draw it above that turn.
+        ///
+        /// It exists because the live Claude Code path cannot record the
+        /// message where it belongs. The CLI says nothing about a peer
+        /// message until the turn's `result` -- see
+        /// `claude::translate` -- so the event is appended after
+        /// everything it caused, and an append-only transcript cannot go
+        /// back and insert it. Carrying the position instead keeps one
+        /// order on the wire and one order on screen without a second
+        /// source for either.
+        ///
+        /// Filled in by the pump, which is the only place that knows a
+        /// seq, and only where a turn was open: `None` for a message read
+        /// out of a session file by `import`, which already has it in the
+        /// right place, and for one that started no turn.
+        #[serde(default, skip_serializing_if = "Option::is_none")]
+        turn_start: Option<u64>,
     },
     /// The manager's record of a question being answered, so a rendered
     /// question card resolves on every device, not just the one that