fix(input): fiabilise la livraison de délégation et journalise le submit

Durcit le portail d'écriture de délégation et son acheminement bout-en-bout
(commande Tauri → orchestrateur → file d'entrée infrastructure → portail
frontend), avec une journalisation du submit pour diagnostiquer les cas où la
délégation n'était pas remise. Couvre le portail d'écriture côté front
(useWritePortal) avec ses tests.

QA : checks application/front/infrastructure/app-tauri verts. Les tests loopback
socket Unix réels ne sont pas exécutables en sandbox (UnixListener::bind →
PermissionDenied) ; alternatives avec skips vertes.

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

crates/app-tauri/src/commands.rs

@@ -364,7 +364,46 @@ pub fn write_terminal(
     state: State<'_, AppState>,
 ) -> Result<(), ErrorDto> {
     let input = request.into_input()?;
-    state.write_terminal.execute(input).map_err(ErrorDto::from)
+    let session_id = input.session_id;
+    let bytes = input.data.len();
+    let control = describe_terminal_write(&input.data);
+    application::diag!(
+        "[pty-write] write_terminal start: session={session_id} bytes={bytes} control={control}"
+    );
+    match state.write_terminal.execute(input) {
+        Ok(()) => {
+            application::diag!(
+                "[pty-write] write_terminal ok: session={session_id} bytes={bytes} control={control}"
+            );
+            Ok(())
+        }
+        Err(e) => {
+            application::diag!(
+                "[pty-write] write_terminal failed: session={session_id} bytes={bytes} \
+                 control={control} error={e}"
+            );
+            Err(ErrorDto::from(e))
+        }
+    }
+}
+
+fn describe_terminal_write(data: &[u8]) -> String {
+    if data.is_empty() {
+        return "<empty>".to_owned();
+    }
+    if data.len() > 16 {
+        return "<bulk>".to_owned();
+    }
+    data.iter()
+        .map(|byte| match *byte {
+            b'\r' => "\\r".to_owned(),
+            b'\n' => "\\n".to_owned(),
+            0x7f => "\\x7f".to_owned(),
+            byte if byte < 0x20 => format!("\\x{byte:02x}"),
+            byte => char::from(byte).to_string(),
+        })
+        .collect::<Vec<_>>()
+        .join("")
 }
 
 /// `resize_terminal` — resize a live PTY.
@@ -1479,6 +1518,10 @@ pub async fn delegation_delivered(
     let project = resolve_project(&request.project_id, &state).await?;
     let agent_id = parse_agent_id(&request.agent_id)?;
     let ticket = parse_ticket_id(&request.ticket)?;
+    application::diag!(
+        "[delivery] delegation_delivered command: project={} agent={agent_id} ticket={ticket}",
+        project.id
+    );
     state
         .orchestrator_service
         .note_delegation_delivered(&project, agent_id, ticket);
@@ -1502,6 +1545,10 @@ pub async fn set_front_attached(
     state: State<'_, AppState>,
 ) -> Result<(), ErrorDto> {
     let agent_id = parse_agent_id(&request.agent_id)?;
+    application::diag!(
+        "[delivery] set_front_attached command: agent={agent_id} attached={}",
+        request.attached
+    );
     state
         .orchestrator_service
         .set_agent_front_attached(agent_id, request.attached);