feat: whatsapp account/friend/message scrapers

Mirrors the WeChat scraper patterns (M3) using the shared paginator +
parser + repo building blocks. Three new async generators yield
snake_case dicts + verbatim raw_json, ready for the channel-generic
upsert_customer / upsert_messages repos.

- app/scraper/whatsapp.py (new): scrape_whatsapp_accounts /
  scrape_whatsapp_friends (page-number pagination over the
  data.overviews / data.totalCount envelope) and scrape_whatsapp_messages
  (backward-cursor pagination, JSON body {uid,friendUid,start,end} —
  NOT form-encoded like WeChat msg/chats). Drops type==-2 dividers;
  maps mediaName -> file_url as a deferred-download key.
- app/scraper/parsers.py: add normalize_whatsapp_type (0->text,
  1->image, -2->divider, else unknown; never raises) and a shared
  coerce_int_or_none scraper helper (mirrors repos._coerce_int so the
  scraper emits type_raw ints without a DB dependency).
- app/storage/repos.py: add upsert_whatsapp_account (PK uid) which
  also upserts the embedded Staff(user_id, name) via the existing
  upsert_staff_from_account helper; WhatsappAccount imported.

Tests (respx mocks, no network): 3 cassette fixtures + 3 scraper test
modules (accounts/friends/messages), parsers + repos extended with WA
cases. Divider drop, backward-cursor advance (end == E1-1), JSON body
asserts, embedded-staff upsert, and channel-generic Customer/Message
upserts all covered.

Suite: 182 -> 211 passing. ruff clean.

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

yunke-server/app/storage/repos.py

@@ -63,6 +63,7 @@ from app.db.models import (
     PhoneCall,
     Staff,
     WechatAccount,
+    WhatsappAccount,
 )
 
 __all__ = [
@@ -76,6 +77,7 @@ __all__ = [
     "upsert_staff_from_account",
     "upsert_voice_call",
     "upsert_wechat_account",
+    "upsert_whatsapp_account",
 ]
 
 
@@ -411,6 +413,25 @@ async def upsert_staff_from_account(session: AsyncSession, rec: dict[str, Any])
     await upsert_staff(session, staff_rec)
 
 
+async def upsert_whatsapp_account(session: AsyncSession, rec: dict[str, Any]) -> None:
+    """Idempotently upsert a :class:`WhatsappAccount` AND its embedded Staff row.
+
+    PK = ``uid`` (of the form ``<phone>@s.whatsapp.net``). Mirrors
+    :func:`upsert_wechat_account`: the companion :func:`upsert_staff_from_account`
+    covers the embedded staff row (``user_id`` + ``user_name``); this helper
+    calls it automatically so an account scrape that lands accounts also lands
+    the owning staff — callers do not need to upsert staff separately.
+
+    The WA account payload (unlike the WeChat one) DOES carry ``sale_phone``,
+    so the embedded staff row picks it up via the shared staff-from-account
+    helper. The staff upsert is best-effort: an account record with no
+    ``user_id`` still writes the account row; the staff upsert silently
+    no-ops.
+    """
+    await _upsert_one(session, WhatsappAccount, rec)
+    await upsert_staff_from_account(session, rec)
+
+
 # ---------------------------------------------------------------------------
 # ChatGroup + GroupMember upsert (M2)
 # ---------------------------------------------------------------------------