feat(ingest): API Push 短新闻数据层

- alembic 0008:articles 加 is_short_news/external_id/source_ref/content_hash
  (UNIQUE);sources.kind 加 'api_push';api_tokens 加 purpose + source_id
- SourceKind.API_PUSH enum;Article/ApiToken model 加新字段
- enrichment_article 短新闻跳过 format/image;
  enrichment_loop SQL 加 is_short_news 路径(并入'可 enrich' 条件)
- 入库侧由 commit 2(ingest 接口)负责:写 body_zh_text=body_text,
  format/image/commentary_meituan_status='n/a',
  classify/commentary_status='pending'(带 tags 时 classify='ok')

无迁移爆炸半径:articles.url 保持 NOT NULL,短新闻合成 api-push:// 占位

backend/app/models/api_token.py

@@ -1,14 +1,19 @@
-"""API Token(给 Android 用,可独立撤销)。"""
+"""API Token(给 Android + API Push 短新闻 ingest 用,可独立撤销)。"""
 from __future__ import annotations
 
 from datetime import datetime
 
-from sqlalchemy import DateTime, ForeignKey, String, func
+from sqlalchemy import DateTime, ForeignKey, Integer, String, func
 from sqlalchemy.orm import Mapped, mapped_column
 
 from app.database import Base
 
 
+# Token 用途
+TOKEN_PURPOSE_MOBILE = "mobile"    # Android 客户端
+TOKEN_PURPOSE_INGEST = "ingest"    # API Push 短新闻 /api/v1/ingest
+
+
 class ApiToken(Base):
     __tablename__ = "api_tokens"
 
@@ -19,6 +24,13 @@ class ApiToken(Base):
     name: Mapped[str] = mapped_column(String(64), nullable=False)  # "Xiaomi-14"
     token_hash: Mapped[str] = mapped_column(String(128), unique=True, nullable=False, index=True)
     # 只存 hash,原始 token 一次性返回给用户
+    purpose: Mapped[str] = mapped_column(
+        String(16), default=TOKEN_PURPOSE_MOBILE, nullable=False, index=True
+    )
+    # ingest 专用:绑定的 source_id(purpose=ingest 时使用,mobile 时为 NULL)
+    source_id: Mapped[int | None] = mapped_column(
+        ForeignKey("sources.id", ondelete="CASCADE"), nullable=True, index=True
+    )
     last_used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     expires_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
     revoked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))