feat(commentary): 双 provider 评论 — Angel(Agnes) + 美团大模型(LongCat)

- 新增 articles.commentary_meituan{_status,_model,_error} 4 列 + commentary_engine
- LlmSetting 加 meituan_api_key/base_url/chat_model/interval_sec/enabled/commentary_prompt
- 新 app/services/llm/providers.py 工厂,支持多 provider 客户端
- enrichment 流程改为 commentary_angel + commentary_meituan 并行(asyncio.gather),
  任一 provider 失败不影响另一个
- enrichment_loop 状态判定:任一 provider 状态不是 ok 都视为待 enrich
- alembic 0004_dual_commentary 迁移
- 前端 Feed 卡片 + ArticleDetail 详情页各加一条'美团评论'卡
- AdminLlmSettings 加美团 provider 配置卡(独立 api_key 编辑器,不回显明文)
- LlmSettingOut.meituan_api_key_set (bool) 替代直接回传 key
- 默认 URL https://api.longcat.chat/openai/v1 / 默认模型 LongCat-2.0-Preview

backend/alembic/versions/0004_dual_commentary.py

@@ -0,0 +1,128 @@
+"""双 provider 评论:加美团评论列 + commentary_engine 标识
+
+- commentary_engine 区分"实际写入的 provider 名称"(angel / meituan / "angel,meituan")
+- commentary_meituan{_status,_model,_error,_} 4 列
+
+Revision ID: 0004
+Revises: 0003
+Create Date: 2026-06-12
+"""
+from __future__ import annotations
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0004"
+down_revision: Union[str, None] = "0003"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # === articles:加 5 列(4 个 status/model/error + 1 个 content)===
+    op.add_column(
+        "articles",
+        sa.Column("commentary_engine", sa.String(32), nullable=True),
+    )
+    op.add_column(
+        "articles",
+        sa.Column(
+            "commentary_meituan",
+            sa.Text,
+            nullable=True,
+        ),
+    )
+    op.add_column(
+        "articles",
+        sa.Column(
+            "commentary_meituan_status",
+            sa.String(16),
+            nullable=False,
+            server_default="n/a",
+        ),
+    )
+    op.add_column(
+        "articles",
+        sa.Column(
+            "commentary_meituan_model",
+            sa.String(64),
+            nullable=True,
+        ),
+    )
+    op.add_column(
+        "articles",
+        sa.Column(
+            "commentary_meituan_error",
+            sa.Text,
+            nullable=True,
+        ),
+    )
+    # 旧存量:commentary_status=ok 的文章 → 标记 commentary_engine=angel
+    op.execute(
+        "UPDATE articles SET commentary_engine = 'angel' "
+        "WHERE commentary_status = 'ok' AND commentary_engine IS NULL"
+    )
+
+    # === llm_settings:加 6 列(美团 provider 配置)===
+    op.add_column(
+        "llm_settings",
+        sa.Column("meituan_api_key", sa.Text, nullable=False, server_default=""),
+    )
+    op.add_column(
+        "llm_settings",
+        sa.Column(
+            "meituan_base_url",
+            sa.String(255),
+            nullable=False,
+            server_default="https://api.longcat.chat/openai/v1",
+        ),
+    )
+    op.add_column(
+        "llm_settings",
+        sa.Column(
+            "meituan_chat_model",
+            sa.String(64),
+            nullable=False,
+            server_default="LongCat-2.0-Preview",
+        ),
+    )
+    op.add_column(
+        "llm_settings",
+        sa.Column(
+            "meituan_interval_sec",
+            sa.Float,
+            nullable=False,
+            server_default="2.0",
+        ),
+    )
+    op.add_column(
+        "llm_settings",
+        sa.Column(
+            "meituan_enabled",
+            sa.Boolean,
+            nullable=False,
+            server_default=sa.true(),
+        ),
+    )
+    op.add_column(
+        "llm_settings",
+        sa.Column("meituan_commentary_prompt", sa.Text, nullable=True),
+    )
+
+
+def downgrade() -> None:
+    # 反向顺序很重要(后加的先删)
+    op.drop_column("llm_settings", "meituan_commentary_prompt")
+    op.drop_column("llm_settings", "meituan_enabled")
+    op.drop_column("llm_settings", "meituan_interval_sec")
+    op.drop_column("llm_settings", "meituan_chat_model")
+    op.drop_column("llm_settings", "meituan_base_url")
+    op.drop_column("llm_settings", "meituan_api_key")
+
+    op.drop_column("articles", "commentary_meituan_error")
+    op.drop_column("articles", "commentary_meituan_model")
+    op.drop_column("articles", "commentary_meituan_status")
+    op.drop_column("articles", "commentary_meituan")
+    op.drop_column("articles", "commentary_engine")