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/domain/src/events.rs

@@ -2,6 +2,7 @@
 //! presentation layer (ARCHITECTURE §3.2).
 
 use crate::ids::{AgentId, ProfileId, ProjectId, SessionId, SkillId, TemplateId};
+use crate::mailbox::TicketId;
 use crate::memory::MemorySlug;
 use crate::template::TemplateVersion;
 
@@ -173,6 +174,28 @@ pub enum DomainEvent {
         /// Whether the in-process ONNX capability (`localOnnx`) is compiled in.
         vector_onnx_enabled: bool,
     },
+    /// A delegation is ready to be injected into the agent's **native terminal**
+    /// (ARCHITECTURE §20.2/§20.3). Published when a turn *starts* (Idle→Busy); the
+    /// backend stays the authority of the FIFO/busy state and **no longer writes the
+    /// turn into the PTY** — the frontend cell runs the write-portal handshake and
+    /// writes `text` + `submit_sequence` through the single PTY writer (the front).
+    /// Discrete, low-frequency (one per delegation). Relayed to the front as
+    /// `delegationReady` like every other [`DomainEvent`].
+    DelegationReady {
+        /// The target agent whose terminal will receive the delegation.
+        agent_id: AgentId,
+        /// The mailbox ticket correlating this turn (acked back via
+        /// `delegation_delivered`); the requester's `ask` is woken by `idea_reply`.
+        ticket: TicketId,
+        /// The task text to inject (written without a trailing `\n` by the portal).
+        text: String,
+        /// Target profile's submit sequence (the cell applies it after the text).
+        /// `None` ⇒ the front applies its default (`"\r"`); never hard-coded in the
+        /// domain.
+        submit_sequence: Option<String>,
+        /// Target profile's submit delay in ms. `None` ⇒ front default (~60 ms).
+        submit_delay_ms: Option<u32>,
+    },
     /// Raw PTY output (usually routed to a dedicated channel, not this bus).
     PtyOutput {
         /// The session.