feat(sync): 聊天图片本地化(message media_hash+download_message_images+local-first rendering)

- Message 模型新增 media_hash 列 (sha256 FK -> Media.media_hash)
- Alembic 迁移 e5f6a7b8c9d0_message_media_hash (batch_alter_table, SQLite/MySQL 通用)
- app/scraper/media.py:download_message_images 批量下载器，镜像 download_call_recordings
  - 候选: media_hash IS NULL AND channel IN ('wechat','whatsapp') AND type IN ('image','video','file') AND 任一 file_*_url LIKE 'http%'
  - image 类型优先 file_th_url (缩略图，小快省)，video/file 优先 file_url
  - per-row try/except + per-run tried set，失败不挂循环
- sync_message_images orchestrator 入口 + ENTITY_MESSAGE_IMAGES 常量 (提交自身 SyncRun，镜像 call_recordings)
- scheduler: _run_message_images + ENTITY_FUNCS['message_images'] + 加入 daily all job (尾部)
- MessageOut schema 暴露 media_hash 字段
- MessageBubble.vue local-first: media_hash 优先 /api/media/{hash}，否则回退 OSS file_url/file_th_url/file_hd_url
- types.ts: Message 接口添加 media_hash 字段
- 新增 test_message_images_downloader.py (6 tests, 镜像 test_recording_downloader)

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

yunke-server/app/sync/orchestrator.py

@@ -53,6 +53,7 @@ from app.db.models import Department, SyncRun, WechatAccount, WhatsappAccount
 from app.scraper.call import scrape_phone_calls, scrape_sms
 from app.scraper.media import (
     download_call_recordings,
+    download_message_images,
     download_message_media,
     download_voice_clip_audio,
 )
@@ -92,11 +93,13 @@ logger = logging.getLogger(__name__)
 
 __all__ = [
     "ENTITY_CALL_RECORDINGS",
+    "ENTITY_MESSAGE_IMAGES",
     "ENTITY_VOICE_CLIP_AUDIO",
     "SyncResult",
     "sync_all_wechat",
     "sync_call_recordings",
     "sync_departments",
+    "sync_message_images",
     "sync_phone_calls",
     "sync_sms",
     "sync_voice_clip_audio",
@@ -157,6 +160,12 @@ ENTITY_VOICE_CLIP = "voice_clip"
 # object store (records a SyncRun with this entity_type; no SyncState row
 # because the voice_clip table itself is the cursor). Mirrors call_recordings.
 ENTITY_VOICE_CLIP_AUDIO = "voice_clip_audio"
+# Message image / media localization pass: not a scrape — reads already-mirrored
+# ``message`` rows whose ``file_url`` / ``file_th_url`` / ``file_hd_url`` point
+# at OSS and have no ``media_hash`` yet, downloads each into the local object
+# store (records a SyncRun with this entity_type; no SyncState row because the
+# message table itself is the cursor). Mirrors call_recordings / voice_clip_audio.
+ENTITY_MESSAGE_IMAGES = "message_images"
 
 CHANNEL_WECHAT = "wechat"
 CHANNEL_WHATSAPP = "whatsapp"
@@ -1152,6 +1161,60 @@ async def sync_voice_clip_audio(
         )
 
 
+async def sync_message_images(
+    session: AsyncSession, client: YunkeClient, store: ObjectStore
+) -> SyncResult:
+    """Download localized copies of chat-message media for already-mirrored
+    messages.
+
+    Not a scrape: reads local ``message`` rows whose ``file_url`` /
+    ``file_th_url`` / ``file_hd_url`` point at OSS, have ``type`` in
+    ('image', 'video', 'file'), are on the wechat / whatsapp channel, and have
+    no ``media_hash`` yet; downloads each and links it. Records a ``SyncRun``
+    (``entity_type='message_images'``); ``fetched`` = messages needing
+    download, ``upserted`` = messages localized.
+
+    Mirrors :func:`sync_call_recordings` / :func:`sync_voice_clip_audio`
+    exactly (same commit semantics): commits its own ``SyncRun`` row because
+    :func:`download_message_images` commits per batch internally, so the run
+    bookkeeping must land in the same transaction boundary to stay consistent
+    with what was actually persisted.
+
+    Failure policy mirrors every other ``sync_*``: a downloader exception is
+    recorded as a ``status='failed'`` ``SyncRun`` and a failed
+    :class:`SyncResult` is returned (no re-raise), so a broken image pass does
+    NOT abort a multi-entity batch.
+    """
+    run = await _start_run(session, ENTITY_MESSAGE_IMAGES)
+    try:
+        attempted, localized = await download_message_images(
+            client, store, session
+        )
+        await _finish_run(
+            session, run, status="success", fetched=attempted, upserted=localized
+        )
+        await session.commit()
+        return SyncResult(
+            entity=ENTITY_MESSAGE_IMAGES,
+            status="success",
+            fetched=attempted,
+            upserted=localized,
+        )
+    except Exception as exc:
+        logger.exception("sync_message_images failed")
+        await _finish_run(
+            session, run, status="failed", fetched=0, upserted=0, error=repr(exc)
+        )
+        await session.commit()
+        return SyncResult(
+            entity=ENTITY_MESSAGE_IMAGES,
+            status="failed",
+            fetched=0,
+            upserted=0,
+            error=repr(exc),
+        )
+
+
 # ---------------------------------------------------------------------------
 # Coordinator
 # ---------------------------------------------------------------------------