fix(tickets): normalise createdBy manquant sur les payloads legacy

Les tickets legacy sans champ createdBy faisaient noircir la fenêtre
tickets côté frontend. Les adapters (ticket.ts, streamGateways.ts)
normalisent désormais ce champ absent, avec couverture de test dédiée.

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

frontend/src/adapters/http/ticketGateway.test.ts

@@ -0,0 +1,82 @@
+import { describe, it, expect, vi } from "vitest";
+
+import { HttpTicketGateway } from "./streamGateways";
+import type { HttpInvoker } from "./httpInvoker";
+import type { WsLiveClient } from "./wsLiveClient";
+
+function gateway(result: unknown): {
+  gw: HttpTicketGateway;
+  invoke: ReturnType<typeof vi.fn>;
+} {
+  const invoke = vi.fn().mockResolvedValue(result);
+  const http = { invoke } as unknown as HttpInvoker;
+  const ws = {} as unknown as WsLiveClient;
+  return { gw: new HttpTicketGateway(http, ws), invoke };
+}
+
+describe("HttpTicketGateway normalization", () => {
+  it("normalizes legacy ticket list rows that omit assignedAgentIds and createdBy", async () => {
+    const { gw } = gateway({
+      items: [
+        {
+          ref: "#12",
+          path: ".ideai/tickets/12/issue.md",
+          title: "Legacy row",
+          status: "open",
+          priority: "medium",
+          updatedAt: 1,
+        },
+      ],
+    });
+
+    const list = await gw.list("proj-1");
+
+    expect(list.items[0]?.assignedAgentIds).toEqual([]);
+    expect(list.items[0]?.createdBy).toEqual({ kind: "user" });
+  });
+
+  it("normalizes legacy ticket payloads that omit array fields and actors", async () => {
+    const { gw } = gateway({
+      id: "issue-1",
+      ref: "#12",
+      number: 12,
+      title: "Legacy",
+      description: "",
+      status: "open",
+      priority: "medium",
+      createdAt: 1,
+      updatedAt: 1,
+      version: 1,
+    });
+
+    const ticket = await gw.read("proj-1", "#12", true);
+
+    expect(ticket.links).toEqual([]);
+    expect(ticket.assignedAgentIds).toEqual([]);
+    expect(ticket.attachments).toEqual([]);
+    expect(ticket.createdBy).toEqual({ kind: "user" });
+    expect(ticket.updatedBy).toEqual({ kind: "user" });
+  });
+
+  it("normalizes malformed ticket actors", async () => {
+    const { gw } = gateway({
+      id: "issue-1",
+      ref: "#12",
+      number: 12,
+      title: "Legacy",
+      description: "",
+      status: "open",
+      priority: "medium",
+      createdBy: { kind: "agent" },
+      updatedBy: { kind: "unknown" },
+      createdAt: 1,
+      updatedAt: 1,
+      version: 1,
+    });
+
+    const ticket = await gw.read("proj-1", "#12", true);
+
+    expect(ticket.createdBy).toEqual({ kind: "user" });
+    expect(ticket.updatedBy).toEqual({ kind: "user" });
+  });
+});