fix(chat): capture du final et cause réelle des fins de tour « Le modèle n'a renvoyé aucune réponse. » — #231

crates/app-tauri/src/chat.rs

@@ -35,6 +35,11 @@ use domain::ports::{
 };
 
 use crate::dto::{ReplyChunk, ReplyProgressDto, ReplyProgressKindDto, ReplyProgressStageDto};
+
+/// Visible terminal message when a structured stream ends without the authoritative
+/// `ReplyEvent::Final`.
+pub const MODEL_RESPONSE_NOT_FINALIZED_MESSAGE: &str =
+    "La réponse du modèle n'a pas pu être finalisée.";
 use crate::stream::TauriChannelSink;
 
 /// Maximum number of recent chat chunks retained for transport reattach replay.
@@ -338,3 +343,12 @@ pub fn chunk_from_event(event: ReplyEvent) -> Option<ReplyChunk> {
         ReplyEvent::RateLimited { .. } => None,
     }
 }
+
+/// Terminal wire chunk for an exhausted structured stream that never produced the
+/// authoritative `ReplyEvent::Final`.
+#[must_use]
+pub fn unfinished_turn_chunk() -> ReplyChunk {
+    ReplyChunk::Error {
+        message: MODEL_RESPONSE_NOT_FINALIZED_MESSAGE.to_owned(),
+    }
+}