v0.7.9 — health fix for HTTP transports, one-time doctor star hint

Fixed

• mcptoon health no longer crashes on HTTP-transport servers: health passed
  http_url= to MCPClient, which only accepts http=, so every HTTP server
  check died with TypeError instead of reporting a status
  (#18, reported by @examosa). Regression tests now construct a real
  MCPClient with the exact kwargs health passes — the old suite stubbed the
  whole class, which is how this slipped past 792 green tests.

Added

• mcptoon doctor prints a one-time GitHub star hint after a fully healthy
  run. Human output only: at most once per machine (cache marker), never in
  CI, suppressible via MCPTOON_NO_STAR_HINT=1; failing runs and structured
  outputs stay untouched.

Full changelog: https://github.com/activeing123/mcptoon/blob/main/CHANGELOG.md