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/app-tauri/tests/dto_chat.rs

@@ -8,9 +8,9 @@
 
 use app_tauri_lib::dto::{CellKind, ReattachChatDto, ReplyChunk, TerminalSessionDto};
 use application::{LaunchAgentOutput, StructuredSessionDescriptor};
-use domain::{AgentId, NodeId, PtySize, SessionKind, SessionStatus, TerminalSession};
 use domain::project::ProjectPath;
 use domain::SessionId;
+use domain::{AgentId, NodeId, PtySize, SessionKind, SessionStatus, TerminalSession};
 use serde_json::json;
 use uuid::Uuid;
 
@@ -49,8 +49,12 @@ fn reply_chunk_final_serialises_exact_camel_case() {
 fn reply_chunk_round_trips_through_json_for_every_variant() {
     for chunk in [
         ReplyChunk::TextDelta { text: "x".into() },
-        ReplyChunk::ToolActivity { label: "runs".into() },
-        ReplyChunk::Final { content: "y".into() },
+        ReplyChunk::ToolActivity {
+            label: "runs".into(),
+        },
+        ReplyChunk::Final {
+            content: "y".into(),
+        },
     ] {
         let v = serde_json::to_value(&chunk).unwrap();
         let back: ReplyChunk = serde_json::from_value(v).unwrap();
@@ -84,7 +88,9 @@ fn reattach_chat_dto_serialises_camel_case_with_typed_scrollback() {
         session_id: "sess-1".into(),
         scrollback: vec![
             ReplyChunk::TextDelta { text: "Hi".into() },
-            ReplyChunk::Final { content: "Hi".into() },
+            ReplyChunk::Final {
+                content: "Hi".into(),
+            },
         ],
     };
     let v = serde_json::to_value(&dto).unwrap();