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/ports/index.ts

@@ -707,10 +707,16 @@ export interface ConversationGateway {
   ): Promise<TurnPage>;
 }
 
-/** Filter/search criteria for {@link TicketGateway.list}. */
+/**
+ * Filter/search criteria for {@link TicketGateway.list} (ticket #12).
+ *
+ * Status and priority are **multi-select**: `statuses`/`priorities` are sets of
+ * accepted values with OR semantics *within* a facet and AND *across* facets. An
+ * empty or absent array means "no constraint on this facet" (all values pass).
+ */
 export interface TicketListQuery {
-  status?: TicketStatus;
-  priority?: TicketPriority;
+  statuses?: TicketStatus[];
+  priorities?: TicketPriority[];
   assignedAgentId?: string;
   /** Free-text match over title/description. */
   text?: string;