feat(frontend): tickets/sprints surface for the web workspace (#86 lot 2)

Adds a Live/Tickets/Sprints tab navigation to WebWorkspace after a project
is opened — a mobile-first adaptation, not a port of the desktop docks/
floating windows, per carnet #86. The web-server transport (17 ticket_*/
sprint_* commands) and the HttpTicketGateway were already wired (lot 1 +
pre-existing gateway code); this lot is UI only.

- Tickets tab: search/filters, list grouped by sprint, create screen,
  detail view with stacked accordion sections (Résumé/Statut et priorité/
  Carnet open by default; Agents assignés/Liens/Zone dangereuse collapsed),
  delete confirmation, optimistic-concurrency conflict banner.
- Sprints tab: create/rename/reorder (Monter/Descendre)/delete with
  confirmation, add tickets via a mobile full-screen ticket picker (never
  a small desktop modal), "Voir tickets" filters the Tickets tab to one
  sprint.
- Reuses the transport-neutral hooks as-is (useTickets, useTicketDetail,
  useTicketSearch) — only presentation and copy are web-specific, in
  French per decision #78 (new local label module, not a reuse of the
  English desktop ticketMeta labels).
- Workaround: `list_agents` isn't in the web-server allowlist, so agent
  names/assignment options are derived from `get_project_work_state`
  (already used by the Live tab) instead of the desktop's useProjectAgents.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/features/tickets/index.ts

@@ -36,4 +36,7 @@ export {
   statusLabel,
   priorityLabel,
   linkKindLabel,
+  TICKET_STATUSES,
+  TICKET_PRIORITIES,
+  TICKET_LINK_KINDS,
 } from "./ticketMeta";