mcptoon 0.7.18 — a first run that actually works

Two defects made the first mcptoon quickstart on a clean machine look broken: it recommended five npm packages that no longer exist, and a server that logged more than one pipe buffer deadlocked the spec="auto" probe (#19). Both are fixed.

Fixed

• mcptoon quickstart proposed five dead npm packages. The zero-config list
  sent npx after names that no longer exist on the npm registry —
  @modelcontextprotocol/server-fetch, -time, -git, -docker and
  -sqlite — so on a clean machine the very first quickstart came back with
  npm error 404 / PROCESS_DIED for five of the eight servers it had just
  recommended. The official reference servers are split by ecosystem:
  filesystem, memory and sequential-thinking are npm packages, while
  fetch, time, git and sqlite are Python packages on PyPI. The npm list
  now contains only packages verified to exist there, the Python servers are
  offered through uvx and only when uvx is installed, the unmaintained
  docker guess is gone, and mcptoon init's sample config no longer ships the
  dead fetch entry. This was the same bug class as the 2026-09-05 demo.py
  fix; that fix deliberately left the discovery candidates alone, which is why
  quickstart kept advertising them.
• A server that logged more than one pipe buffer deadlocked the spec="auto"
  probe (#19). _spawn_stdio() opened the child with
  stderr=subprocess.PIPE, and nothing read that pipe while the server was
  alive: a server logging more than a few KB blocked inside write(), stopped
  reading stdin and stopped answering stdout, and every request then timed out
  as RESPONSE_TIMEOUT ... server went silent. One server/discover probe was
  enough to trigger it — the Python reference servers answer that unknown method
  with ~6.8 KB of pydantic validation warnings (measured: 6,793 bytes from
  uvx mcp-server-time) — which made uvx mcp-server-fetch|time|git look dead
  on a fresh machine while spec="legacy" worked, because legacy never probes.
  stderr is now drained continuously on a background thread, in 8 KB chunks via
  read1 (so a single huge line with no newline is drained too, which line
  iteration would not), and the bounded drained ring feeds _stderr_tail().
  The post-mortem pipe read it replaces was both the reader that was missing and
  a race against process exit.

The release also re-pins the footprint claims, because the fixes moved them: the
wheel is 189KB (194,028 bytes) and src/mcptoon/*.py is 15,697 physical
lines, and the suite total moves to 1,061 tests (1,060 passed, 1 skipped).
Both README badges, the landing pages, DEVELOPERS.md, ROADMAP.md,
docs/comparison.md, docs/tiktoken-benchmarks.md and the shipped skill cards
were updated together — the footprint guard reads all of them, so a partial
update is a red CI.

Verify: pip install --upgrade mcptoon (wheel 189KB, zero dependencies).