0.61.0

Added

• session start --client-id <id> and the google_client_id setting choose your own Google app (WC-SECR-25):
  --client-file or --client-id, then DRIVE_GOOGLE_CLIENT_ID, then the profile's or the defaults'
  google_client_id, then WireCat's app. The secret comes from DRIVE_GOOGLE_CLIENT_SECRET, never the settings file,
  and session start warns before the browser opens when your app has none. doctor reports "source": "config"
  for the defaults' setting. An agent over MCP cannot change google_client_id.

Fixed

• files download and files export stream to disk, so large files download. Files over 50 MB failed with
  provider_unavailable because the whole file was read into memory. The bytes now go to a temporary file next to
  --output, which replaces the target only when the download is complete. There is no size limit; a download stops
  only after a minute with no data.
• The Google sign-in notes no longer describe WireCat's review status. They say that making a shared Google app
  public for Drive is complex, so Google may refuse the sign-in, and point to your own Google app. No behaviour changes.
• Signing a profile in again keeps its settings: mirrors, max_text_chars, picture_search and the rest stayed
  only as the principal, folders and storage before.

Changed — may break callers

• doctor's oauth_client says where the Google app comes from: { "client": "wirecat", "source": "constants" },
  or "own" with "flag" (--client-file) or "env" (DRIVE_GOOGLE_CLIENT_ID). WireCat's app now comes from
  cli-core's constants.json instead of drive's source; the order is unchanged.
• DRIVE_GOOGLE_CLIENT_SECRET without DRIVE_GOOGLE_CLIENT_ID fails with reason sign-in.secret-without-id.
• drive runs on cli-base 0.77.1 and cli-core 0.566.0. A failure can now be conflict (exit 15); the MCP tools'
  error codes list it.