feat(tickets): filtres multi-critères par cases à cocher (backend + frontend)

Passe les filtres de la liste des tickets en sélection multiple (#12).

Backend Rust :
- IssueListFilter : statuses/priorities en Vec, filter_matches en OR intra-champ
  et AND inter-champs
- TicketListRequestDto en tableaux + from_request (parse/déduplication)
- MCP idea_ticket_list aligné sur le nouveau contrat

Frontend :
- TicketListQuery.statuses/priorities
- UI de cases à cocher, toggle/clear des filtres

Tests verts : issue_store (7), app-tauri --lib (59), mcp_server (24),
issue_usecases (6), sprint_usecases (6), frontend vitest (505), npm run build (exit 0).

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

frontend/src/adapters/mock/index.ts

@@ -1951,9 +1951,13 @@ export class MockTicketGateway implements TicketGateway {
   async list(projectId: string, query?: TicketListQuery): Promise<TicketList> {
     const q = query ?? {};
     const text = q.text?.trim().toLowerCase();
+    // Multi-select facets (ticket #12): OR within a facet, AND across facets; an
+    // empty/absent set means "no constraint" (all values pass).
+    const statuses = q.statuses ?? [];
+    const priorities = q.priorities ?? [];
     const rows = [...this.projectTickets(projectId).values()]
-      .filter((t) => !q.status || t.status === q.status)
-      .filter((t) => !q.priority || t.priority === q.priority)
+      .filter((t) => statuses.length === 0 || statuses.includes(t.status))
+      .filter((t) => priorities.length === 0 || priorities.includes(t.priority))
       .filter(
         (t) =>
           !q.assignedAgentId || t.assignedAgentIds.includes(q.assignedAgentId),