-- 迁移 0004(v2.1.0):
--  1) emails 增加 markdown_body 列(入库时从 HTML/纯文本转出的 Markdown 正文,webhook 投递使用)
--  2) API/MCP Key 合并为单一 Key:把最近一条有效凭据的 SHA-256 迁入 settings 表,随后删除 api_credentials 表

ALTER TABLE emails ADD COLUMN markdown_body TEXT;

INSERT INTO settings (key, value)
  SELECT 'api_key_hash', key_hash FROM api_credentials
  WHERE revoked_at IS NULL ORDER BY created_at DESC LIMIT 1;

INSERT INTO settings (key, value)
  SELECT 'api_key_last4', key_last4 FROM api_credentials
  WHERE revoked_at IS NULL ORDER BY created_at DESC LIMIT 1;

INSERT INTO settings (key, value)
  SELECT 'api_key_created_at', created_at FROM api_credentials
  WHERE revoked_at IS NULL ORDER BY created_at DESC LIMIT 1;

DROP TABLE api_credentials;