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>

frontend/src/adapters/agent.ts

@@ -16,9 +16,6 @@ import { Channel, invoke } from "@tauri-apps/api/core";
 
 import type {
   Agent,
-  CellKind,
-  ReattachChatDto,
-  ReplyChunk,
   ResumableAgent,
   TerminalSession,
 } from "@/domain";
@@ -41,8 +38,6 @@ interface LaunchAgentResponse {
   cols: number;
   /** Conversation id minted by this launch (omitted when nothing was assigned). */
   assignedConversationId?: string;
-  /** How the hosting cell should render (`"chat"` ⇒ structured AI cell, §17.6). */
-  cellKind: CellKind;
 }
 
 export class TauriAgentGateway implements AgentGateway {
@@ -155,11 +150,9 @@ export class TauriAgentGateway implements AgentGateway {
 
     const base = makeTerminalHandle(res.sessionId, channel);
     // Surface the id assigned by this launch (so the caller persists it on the
-    // leaf and resumes next time) and the derived `cellKind` (so the leaf routes
-    // to `AgentChatView` vs `TerminalView`, §17.6).
+    // leaf and resumes next time).
     return {
       ...base,
-      cellKind: res.cellKind,
       ...(res.assignedConversationId
         ? { assignedConversationId: res.assignedConversationId }
         : {}),
@@ -197,40 +190,4 @@ export class TauriAgentGateway implements AgentGateway {
       request: { projectId, agentId, conversationId },
     });
   }
-
-  async sendPrompt(
-    sessionId: string,
-    prompt: string,
-    onReply: (chunk: ReplyChunk) => void,
-  ): Promise<void> {
-    // Per-turn reply channel. The backend streams typed `ReplyChunk`s (tagged on
-    // `kind`); the pump runs to the `final` chunk then detaches its generation.
-    const channel = new Channel<ReplyChunk>();
-    channel.onmessage = (chunk) => onReply(chunk);
-
-    // `agent_send` takes top-level args (Tauri renames the snake_case command
-    // params to camelCase): `sessionId`, `prompt`, `onReply`.
-    await invoke("agent_send", { sessionId, prompt, onReply: channel });
-  }
-
-  async reattachChat(
-    sessionId: string,
-    onReply: (chunk: ReplyChunk) => void,
-  ): Promise<ReplyChunk[]> {
-    // Re-bind to a still-living structured session without re-spawning it. The
-    // returned scrollback repaints prior turns; subsequent chunks arrive over the
-    // freshly-registered channel.
-    const channel = new Channel<ReplyChunk>();
-    channel.onmessage = (chunk) => onReply(chunk);
-
-    const res = await invoke<ReattachChatDto>("reattach_agent_chat", {
-      sessionId,
-      onReply: channel,
-    });
-    return res.scrollback;
-  }
-
-  async closeAgentSession(sessionId: string): Promise<void> {
-    await invoke("close_agent_session", { sessionId });
-  }
 }