loopd: a turn's speaker in the log, its number in SessionUpdated

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/loopd/src/turn.rs

@@ -113,19 +113,23 @@ fn map_event(event: &ChatEvent, on_event: &mut dyn FnMut(&TurnEvent)) {
     }
 }
 
+/// One turn of `session`: `content` is the user's message, and `speaker` who spoke it, when one
+/// person did. The speaker is logged on the `User` record, for `memoryd`, and never sent to the
+/// model: the request is the same with a speaker and without one (M5c spec, section 11).
 pub fn run_turn(
     session: &mut Session,
     rt: &Runtime<'_>,
     content: &str,
+    speaker: Option<&str>,
     on_event: &mut dyn FnMut(&TurnEvent),
 ) -> Result<TurnOutcome, TurnError> {
     session
         .append(LogRecord::User {
             time: Timestamp::now(),
             content: neutralise(content).into_owned(),
-            // Set in M5c-1 task 02, from the turn. `None` is not written: the record's bytes
-            // are as before.
-            speaker: None,
+            // As it came: not checked and not neutralised, since it never reaches the model.
+            // `None` is not written, so the record's bytes are as before M5c.
+            speaker: speaker.map(str::to_string),
         })
         .map_err(TurnError::Session)?;