keep ingested chunks findable and structured

Two bugs made self-ingested content useless, both silently:

- _payload wrote `chapter_number` (int) while math retrieval filters on
  `chapter` (the full "فصل ۲: کسر" string), so anything we ingest could
  never match a search — no error, just permanently invisible content.
- ingest_pdf flattened the vision extraction into one text blob and threw
  away type/keywords/generalSolution/problem/solution. LessonChunk is the
  source of truth, so rebuilding meant paying for vision again — and the
  problem/solution pairs are the input for building lesson questions.

LessonChunk now stores those fields and _payload emits them under the same
keys the other team's collections use, so ours and theirs stay one shape.

Also fixes a regression from the whitenoise commit: the Manifest storage
variant raises when staticfiles.json is absent, which broke all 23 admin
rendering tests (Django forces DEBUG=False in tests, so USE_FINDERS is off)
and would have taken the admin panel down entirely the day DEBUG=0 ships
without a collectstatic run.

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

rag/models.py

@@ -24,12 +24,28 @@ class LessonChunk(models.Model):
     lesson_number = models.IntegerField()
     chapter = models.IntegerField(null=True, blank=True)
 
+    # عنوانِ کاملِ فصل، دقیقاً همون رشته‌ای که در payloadِ تیمِ دیگه هست
+    # («فصل ۲: کسر»). retrieval برای ریاضی روی همین مقدار فیلتر می‌کنه، پس
+    # بدونِ این هر چیزی که ingest کنیم در جستجو پیدا نمی‌شه.
+    chapter_title = models.CharField(max_length=255, blank=True)
+    grade_title = models.CharField(max_length=100, blank=True)
+
     order = models.PositiveIntegerField()
     title = models.CharField(max_length=255)
     original_text = models.TextField()
     summary = models.TextField()
     embedding_vector = models.JSONField(null=True, blank=True)
 
+    # --- ساختارِ استخراج‌شده از کتاب (همون قراردادِ ریاضیِ تیمِ دیگه) -------
+    # vision یک‌بار و با هزینه این‌ها رو درمی‌آره؛ اگه فقط متنِ صاف‌شده رو
+    # نگه داریم، برای هر بازسازی باید دوباره همون هزینه رو بدیم. ضمناً
+    # problem/solution ورودیِ مستقیمِ ساختِ سؤال‌های مسیرِ درس‌اند.
+    problem_type = models.CharField(max_length=255, blank=True)
+    keywords = models.JSONField(default=list, blank=True)
+    general_solution = models.TextField(blank=True)
+    problem = models.TextField(blank=True)
+    solution = models.TextField(blank=True)
+
     collection = models.CharField(max_length=200, db_index=True)
     qdrant_point_id = models.UUIDField(default=uuid.uuid4, editable=False)