feat(tickets): surface frontend V1 du système de tickets

Surface UI complète des tickets (domaine Issue exposé « ticket »),
validée QA de bout en bout : cargo build + tests backend verts,
npm run build + npm test (459) verts.

- Domaine : DTO Ticket, 9 events Issue* + guard isTicketEvent.
- Ports : TicketGateway (+ types query/input) ajouté à Gateways.
- Adapters : TauriTicketGateway réel (+ isTicketVersionConflict),
  wiring, et MockTicketGateway pour les tests.
- Feature tickets : hooks (useTickets, useTicketDetail,
  useProjectAgents), TicketsPanel, TicketDetail, TicketsView,
  ticketMeta + tests.
- ProjectsView : onglet sidebar « Tickets ».

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

frontend/src/features/tickets/TicketsView.tsx

@@ -0,0 +1,34 @@
+/**
+ * Tickets feature container: the sidebar list (F2) plus the full-screen detail
+ * overlay (F3/F4/F5/F7). Owns the currently-open `#ref` so a click in the list
+ * — or on any inline `#ref` inside the detail — swaps the overlay to that
+ * ticket.
+ */
+
+import { useState } from "react";
+
+import { TicketsPanel } from "./TicketsPanel";
+import { TicketDetail } from "./TicketDetail";
+
+export interface TicketsViewProps {
+  projectId: string;
+}
+
+export function TicketsView({ projectId }: TicketsViewProps) {
+  const [openRef, setOpenRef] = useState<string | null>(null);
+
+  return (
+    <>
+      <TicketsPanel projectId={projectId} onOpen={setOpenRef} />
+      {openRef && (
+        <TicketDetail
+          key={`${projectId}-${openRef}`}
+          projectId={projectId}
+          ticketRef={openRef}
+          onClose={() => setOpenRef(null)}
+          onOpenRef={setOpenRef}
+        />
+      )}
+    </>
+  );
+}