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/scheduler.py

@@ -57,6 +57,7 @@ from app.sync.orchestrator import (
     sync_all_wechat,
     sync_call_recordings,
     sync_departments,
+    sync_message_images,
     sync_phone_calls,
     sync_sms,
     sync_voice_clip_audio,
@@ -218,6 +219,13 @@ async def _run_voice_clip_audio(
     return [await sync_voice_clip_audio(session, client, store)]
 
 
+async def _run_message_images(
+    session: AsyncSession, client: YunkeClient, store: ObjectStore
+) -> list[SyncResult]:
+    """Image / media localization pass for already-mirrored ``message`` rows."""
+    return [await sync_message_images(session, client, store)]
+
+
 async def _run_messages(
     session: AsyncSession, client: YunkeClient, store: ObjectStore
 ) -> list[SyncResult]:
@@ -301,6 +309,13 @@ async def _run_all(
     # in the daily job means no later in-batch entity can be affected by the
     # mid-batch commit boundary.
     results.append(await sync_voice_clip_audio(session, client, store))
+    # Message image / media localization: download OSS images / videos / files
+    # for already-mirrored ``message`` rows. Runs AFTER messages (synced
+    # earlier in this same daily job via _run_all_wechat + _run_wa_messages)
+    # so freshly-scraped rows are eligible. Commits internally (mirrors
+    # call_recordings / voice_clip_audio) — also placed at the tail of the
+    # daily job for the same mid-batch commit-boundary reason.
+    results.append(await sync_message_images(session, client, store))
     return results
 
 
@@ -324,6 +339,7 @@ ENTITY_FUNCS: dict[
     "voice_clips": _run_voice_clips,
     "call_recordings": _run_call_recordings,
     "voice_clip_audio": _run_voice_clip_audio,
+    "message_images": _run_message_images,
     "messages": _run_messages,
     "wa_messages": _run_wa_messages,
     "all_wechat": _run_all_wechat,