math in Persian text: lists read right-to-left, every content text goes through MathText, chat input picks its direction per line

Measured by rendering every question, option and several tutor answers in
Chrome and comparing the on-screen x of each number (2026-09-29):
- A list inside a sentence ('از −۳ به −۲، −۱، ۰ می‌رسیم', 'الگویِ ۲، ۵، ۸')
  was locked as one left-to-right run, so all 482 read backwards. '،' and
  '؛' outside brackets now split the run; sets and coordinates in brackets
  stay one run. Locked runs are isolates (isolate-override), otherwise the
  comma between two of them was still pulled left-to-right.
- Without MathText 704 of 931 minus signs and 602 of 983 expressions were
  misplaced; lesson and island titles, the lesson intro, unit blurb,
  notification bodies and ticket messages now go through it.
- The chat box takes its direction from each line's first letter, so a
  line of pure math stays left-to-right while typing. A line that starts
  in Persian can still show its math reordered inside the box; a textarea
  cannot isolate part of its text. The sent message renders correctly.

Four expressions with Persian words inside them ('f(x) = (ریشه دوم x) + ۵۰')
remain ambiguous.

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

src/screens/AskScreen.tsx

@@ -173,6 +173,11 @@ export function AskScreen({ lessonId, questionId, prompt }: { lessonId?: number;
               }
             }}
             rows={1}
+            // جهتِ هر خط از اولین حرفش: «-3 + 5» هنگامِ تایپ چپ‌به‌راست می‌ماند. خطی که با
+            // فارسی شروع شود راست‌به‌چپ است و ریاضیِ وسطش در کادرِ تایپ ممکن است جابه‌جا دیده شود؛
+            // در textarea نمی‌شود تکه‌ای را قفل کرد. پیامِ فرستاده‌شده از MathText رد می‌شود.
+            dir={input ? 'auto' : 'rtl'}
+            style={{ unicodeBidi: 'plaintext', textAlign: 'right' }}
             placeholder="سوالت رو بنویس…"
             className="max-h-28 min-h-10 flex-1 resize-none rounded-3xl bg-soft px-4 py-2.5 text-sm leading-6 text-ink outline-none placeholder:text-faint"
           />