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/features/tickets/useTickets.ts

@@ -20,6 +20,8 @@ import {
   type Sprint,
   type Ticket,
   type TicketList,
+  type TicketPriority,
+  type TicketStatus,
 } from "@/domain";
 import type { CreateTicketInput, TicketListQuery } from "@/ports";
 import { useGateways } from "@/app/di";
@@ -32,6 +34,16 @@ export interface TicketsViewModel {
   busy: boolean;
   query: TicketListQuery;
   setQuery: (next: TicketListQuery) => void;
+  /**
+   * Toggles a status in the multi-select filter (ticket #12): adds it when
+   * absent, removes it when present. An empty set ⇒ no status constraint (all).
+   * The list re-fetches automatically as the query changes.
+   */
+  toggleStatus: (status: TicketStatus) => void;
+  /** Toggles a priority in the multi-select filter (ticket #12). */
+  togglePriority: (priority: TicketPriority) => void;
+  /** Clears both facet filters (status + priority), leaving other criteria. */
+  clearFacets: () => void;
   refresh: () => Promise<void>;
   create: (input: CreateTicketInput) => Promise<Ticket | null>;
   /**
@@ -89,6 +101,35 @@ export function useTickets(projectId: string): TicketsViewModel {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [projectId, ticket, queryKey]);
 
+  // Toggle a value in one facet set, dropping the key entirely when it empties
+  // so the query stays clean ("no constraint"). Setting a fresh object identity
+  // re-fetches via the `queryKey` effect (ticket #12).
+  const toggleStatus = useCallback((status: TicketStatus) => {
+    setQuery((prev) => {
+      const current = prev.statuses ?? [];
+      const next = current.includes(status)
+        ? current.filter((s) => s !== status)
+        : [...current, status];
+      const { statuses: _drop, ...rest } = prev;
+      return next.length > 0 ? { ...rest, statuses: next } : rest;
+    });
+  }, []);
+
+  const togglePriority = useCallback((priority: TicketPriority) => {
+    setQuery((prev) => {
+      const current = prev.priorities ?? [];
+      const next = current.includes(priority)
+        ? current.filter((p) => p !== priority)
+        : [...current, priority];
+      const { priorities: _drop, ...rest } = prev;
+      return next.length > 0 ? { ...rest, priorities: next } : rest;
+    });
+  }, []);
+
+  const clearFacets = useCallback(() => {
+    setQuery(({ statuses: _s, priorities: _p, ...rest }) => rest);
+  }, []);
+
   const refreshSprints = useCallback(async () => {
     try {
       setSprints(await ticket.listSprints(projectId));
@@ -242,6 +283,9 @@ export function useTickets(projectId: string): TicketsViewModel {
     busy,
     query,
     setQuery,
+    toggleStatus,
+    togglePriority,
+    clearFacets,
     refresh,
     create,
     assignSprint,