Subjects per grade (math, calculus, geometry, stats, discrete), 5 new textbooks, 202 new islands, long islands split, hand-written figures and lesson texts for the new books

- content.Subject + Unit.subject, /api/home?subject=, tutor grounded in the chosen book
- 5 new books ingested; ~1150 hand-written questions, islands named by hand
- node_split: islands over 7 lessons split into parts of <=6 (lesson ids and progress kept)
- Lesson.figures hand-authored and visually checked for 653 lessons of the new books;
  gen_lesson_figures got --subject and survives network errors
- seed files re-exported

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

content/curriculum_io.py

@@ -102,6 +102,8 @@ def parse(raw: bytes) -> list[dict]:
                 })
 
             clean_units.append({
+                # کتاب صریح است: فایلِ بی‌کتاب رد می‌شود تا فصلِ حسابان بی‌صدا «ریاضی» نشود.
+                'subject': _text(unit.get('subject'), 'subject', uwhere),
                 'title': _text(unit.get('title'), 'title', uwhere),
                 'blurb': str(unit.get('blurb') or '')[:120],
                 'order': int(unit.get('order') or ui + 1),
@@ -117,6 +119,16 @@ def parse(raw: bytes) -> list[dict]:
     return cleaned
 
 
+def _subject_or_error(title: str):
+    """کتابِ فایل باید از قبل در جدولِ Subject باشد (ادمین ← کتاب‌ها)؛ نامِ ناشناخته خطا است، نه ساختنِ بی‌صدا."""
+    from .models import Subject
+    subject = Subject.objects.filter(title=title).first()
+    if subject is None:
+        known = '، '.join(Subject.objects.values_list('title', flat=True))
+        raise CurriculumError(f'کتابِ «{title}» در جدولِ کتاب‌ها نیست. موجود: {known}')
+    return subject
+
+
 @transaction.atomic
 def import_curriculum(grades: list[dict]) -> dict:
     """
@@ -135,9 +147,10 @@ def import_curriculum(grades: list[dict]) -> dict:
         counts['grades'] += 1 if created else 0
 
         for unit_row in grade_row['units']:
+            subject = _subject_or_error(unit_row['subject'])
             unit, created = Unit.objects.get_or_create(
                 grade=grade, title=unit_row['title'],
-                defaults={'order': unit_row['order']},
+                defaults={'order': unit_row['order'], 'subject': subject},
             )
             counts['units'] += 1 if created else 0
             # متنِ ادمین برنده است: فقط خانه‌ی خالی از فایل پر می‌شود
@@ -185,13 +198,14 @@ def import_curriculum(grades: list[dict]) -> dict:
 def export_curriculum(grades_queryset) -> dict:
     """خروجی دقیقاً همان قالبی‌ست که import می‌خواند."""
     out = []
-    for grade in grades_queryset.prefetch_related('units__nodes__lessons'):
+    for grade in grades_queryset.prefetch_related('units__subject', 'units__nodes__lessons'):
         out.append({
             'title': grade.title,
             'icon': grade.icon,
             'color': grade.color,
             'units': [
                 {
+                    'subject': unit.subject.title,
                     'title': unit.title,
                     'order': unit.order,
                     **({'blurb': unit.blurb} if unit.blurb else {}),