feat(agent): conversation par paire + entrée médiée + pivot terminal/MCP

Coeur inter-agents consolidé et surface front réalignée sur la décision
"terminal natif PTY, pas d'UI chat" (Option 1).

Domaine
- nouveaux modules conversation, mailbox, input, fileguard (ports + types)
- orchestrator/profile/events étendus (conversation par paire, FIFO)

Application / Infrastructure
- orchestrator/service + context_guard : sérialisation FIFO par agent,
  garde RW mémoire/contexte, dispatch ask/reply
- adapters in-memory conversation / mailbox / input / fileguard
- registry session + lifecycle agent durcis (1 agent = 1 session vivante)
- outils MCP idea_* alignés sur le nouveau dispatch

Frontend
- MediatedInput + useAgentBusy : entrée utilisateur médiée par IdeA,
  terminal = vue sortie inchangée
- suppression de la vue chat structurée (AgentChatView) — abandonnée
- adapter input + ports mis à jour

Divers
- .ideai/ : mémoire projet + briefs de cadrage versionnés ;
  requests/ runtime ignoré ; agents projet réels (DevBackend/DevFrontend/QA)

Tests : Rust (domain/application/infrastructure/app-tauri) + front (346) verts.

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

crates/app-tauri/src/dto.rs

@@ -1186,6 +1186,31 @@ impl From<LaunchAgentOutput> for TerminalSessionDto {
     }
 }
 
+/// Request DTO for `submit_agent_input` (cadrage C4 §4.2): the human Envoyer path.
+/// The frontend's [`InputGateway`](../../../frontend/src/ports) sends
+/// `{ request: { projectId, agentId, text } }`.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SubmitAgentInputRequestDto {
+    /// Id of the owning project.
+    pub project_id: String,
+    /// Id of the agent to send the human input to.
+    pub agent_id: String,
+    /// The text the operator typed (enqueued as a `from_human` ticket).
+    pub text: String,
+}
+
+/// Request DTO for `interrupt_agent` (cadrage C4 §4.2): the Interrompre path. The
+/// frontend sends `{ request: { projectId, agentId } }`.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct InterruptAgentRequestDto {
+    /// Id of the owning project.
+    pub project_id: String,
+    /// Id of the agent whose running turn to preempt.
+    pub agent_id: String,
+}
+
 /// Request DTO for `change_agent_profile` (§15.1): hot-swap an agent's runtime
 /// profile, optionally relaunching its live session in place.
 #[derive(Debug, Clone, Deserialize)]