lighter first load, math reads left-to-right in quizzes, tickets from the server, readable separators

- Every screen but home is its own chunk and preloads when the browser is
  idle; React and motion get their own long-cached chunks. The app entry
  goes from 505 kB (160 kB gzip) to 85 kB (27 kB gzip).
- Quiz prompts, options and lesson examples go through MathText, so
  '10 + 3 - 7 - 2' reads from the left; an unpaired bracket at the edge of
  a math run stays with the Persian sentence.
- Support lists tickets from GET /support/tickets instead of this
  browser's localStorage; a ticket's messages load when it is opened.
- '·' next to a Persian zero read as another digit ('فصلِ ۱ · ۰' looked
  like ۱۰۰); a thin bar separates them now. Notification bodies show
  Persian digits.
- A root or vertex the model already marked with coordinates is no longer
  labelled a second time on top of it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/api/index.ts

@@ -172,6 +172,8 @@ export const api = {
   support: {
     createTicket: (subject: string, category: string) =>
       http.create<{ ticketId: string; status: string }>('/support/tickets', { subject, category }),
+    /** تیکت‌های همین کاربر، تازه‌ترین اول (۲۰ تای آخر). */
+    tickets: () => http.get<{ tickets: T.TicketSummary[] }>('/support/tickets').then((r) => r.tickets),
     ticket: (ticketId: string) => http.get<T.Ticket>(`/support/tickets/${ticketId}`),
     reply: (ticketId: string, text: string) =>
       http.create<{ messageId: string; success: boolean }>(`/support/tickets/${ticketId}/messages`, { text }),