chore(wip): checkpoint P8/C avant chantier Codex inter-agents

Sauvegarde de l'arbre de travail en cours (persistance P8, conversations
C-series, write-portal frontend, médiation d'entrée) avant d'attaquer le
support de la délégation inter-agents pour les profils Codex.

Le round-trip inter-agent question/réponse est couvert sans tokens par
les tests loopback existants (state::mcp_e2e_loopback_tests).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/application/tests/conversation_record.rs

@@ -61,7 +61,12 @@ impl InMemoryConversationLog {
     }
 
     fn thread(&self, conv: ConversationId) -> Vec<ConversationTurn> {
-        self.threads.lock().unwrap().get(&conv).cloned().unwrap_or_default()
+        self.threads
+            .lock()
+            .unwrap()
+            .get(&conv)
+            .cloned()
+            .unwrap_or_default()
     }
 }
 
@@ -156,11 +161,7 @@ impl HandoffStore for InMemoryHandoffStore {
         Ok(self.store.lock().unwrap().get(&conversation).cloned())
     }
 
-    async fn save(
-        &self,
-        conversation: ConversationId,
-        handoff: Handoff,
-    ) -> Result<(), StoreError> {
+    async fn save(&self, conversation: ConversationId, handoff: Handoff) -> Result<(), StoreError> {
         if let Some(err) = self.fail_save.lock().unwrap().clone() {
             return Err(err);
         }
@@ -219,7 +220,9 @@ async fn single_record_appends_turn_and_advances_handoff() {
     let conv = conv_id(1);
     let t1 = turn(conv, turn_id(10), "hello world");
 
-    uc.record(conv, t1.clone()).await.expect("record should succeed");
+    uc.record(conv, t1.clone())
+        .await
+        .expect("record should succeed");
 
     // Log contains the turn.
     assert_eq!(log.thread(conv), vec![t1.clone()]);
@@ -227,7 +230,11 @@ async fn single_record_appends_turn_and_advances_handoff() {
     // Handoff advanced: up_to == turn id, summary contains the turn text.
     let h = handoffs.loaded(conv).expect("handoff should be saved");
     assert_eq!(h.up_to, t1.id);
-    assert!(h.summary_md.contains("hello world"), "summary={:?}", h.summary_md);
+    assert!(
+        h.summary_md.contains("hello world"),
+        "summary={:?}",
+        h.summary_md
+    );
 
     // First fold: prev = None, exactly one new turn.
     assert_eq!(summarizer.calls(), vec![(false, 1)]);
@@ -254,8 +261,16 @@ async fn two_records_fold_incrementally_without_full_reread() {
     // Handoff up_to == t2.id; summary contains both texts.
     let h = handoffs.loaded(conv).expect("handoff saved");
     assert_eq!(h.up_to, t2.id);
-    assert!(h.summary_md.contains("first-text"), "summary={:?}", h.summary_md);
-    assert!(h.summary_md.contains("second-text"), "summary={:?}", h.summary_md);
+    assert!(
+        h.summary_md.contains("first-text"),
+        "summary={:?}",
+        h.summary_md
+    );
+    assert!(
+        h.summary_md.contains("second-text"),
+        "summary={:?}",
+        h.summary_md
+    );
 
     // Proof of incrementality: prev None then Some, and len == 1 on BOTH calls
     // (never 2 → the whole log is never re-read into the fold).
@@ -311,9 +326,9 @@ async fn load_error_propagates_as_store() {
 #[tokio::test]
 async fn save_error_propagates_as_store() {
     let log = Arc::new(InMemoryConversationLog::default());
-    let handoffs = Arc::new(InMemoryHandoffStore::failing_save(StoreError::Serialization(
-        "save boom".to_owned(),
-    )));
+    let handoffs = Arc::new(InMemoryHandoffStore::failing_save(
+        StoreError::Serialization("save boom".to_owned()),
+    ));
     let summarizer = Arc::new(RecordingSummarizer::default());
     let uc = RecordTurn::new(log.clone(), handoffs.clone(), summarizer.clone());