CodexSwitch v26.9.01.1039

Fixed

• Proxy-backed provider activation now starts and verifies the unified proxy,
  so a subsequent plain codex command no longer reconnects repeatedly to an
  unused loopback port. Startup uses bounded health polling and verifies the
  responding implementation instead of trusting any HTTP 200 on port 14555.
• Configuration and switch-state writes now use atomic replacement, preventing
  interrupted writes from leaving truncated TOML or JSON. Status explicitly
  marks a removed native OpenAI model as invalid instead of presenting stale
  state as healthy.
• Fixed those atomic writes on native Windows by syncing the still-writable
  temporary file instead of reopening it read-only. Selecting an account or
  applying a provider no longer fails with [Errno 9] Bad file descriptor.
• Go upstream requests now inherit client cancellation, credential helpers have
  a bounded timeout, malformed SSE is reported, and server input/header limits
  are explicit.

Changed

• CI now formats, race-tests, vets and builds the active Go proxy in addition to
  the Python matrix. A development requirements file makes the documented local
  pytest workflow reproducible.
• CI now also runs the Python and Commander test suite on native Windows so
  Windows-only file-descriptor and path-escaping regressions are caught.