feat(cli): surface progression intermédiaire, activité MCP, flux agent↔agent — #157 (QA verte)

frontend/src/adapters/mock/index.ts

@@ -838,6 +838,18 @@ export class MockAgentGateway implements AgentGateway {
     }
     const content = `Agent: reçu « ${prompt} ».`;
     const streamed: ReplyChunk[] = [
+      {
+        kind: "progress",
+        progress: {
+          source: "providerNative",
+          kind: "message",
+          stage: "delta",
+          label: "Analyse",
+          text: "Traitement du message en cours.",
+          provider: "mock",
+          nativeEvent: "mock.progress",
+        },
+      },
       { kind: "toolActivity", label: "Analyse du prompt" },
       { kind: "textDelta", text: "Agent: reçu " },
       { kind: "textDelta", text: `« ${prompt} ».` },