RTK is parsing `rspec` default output as json, when it is not.

Error:

⏺ Bash(cd ~/dev/chopin && bundle exec rspec redacted/path/to/my_spec.rb --no-color 2>&1 | grep -E "examples|Failure|passe…)
  ⎿  [rtk] rspec: JSON parse failed (expected value at line 1 column 1), using text fallback

Claude says:

⏺ RTK tries parse rspec output as JSON. Default rspec formatter = progress (text), not json. Fallback works but noisy.

  Options:
  - Ignore warning. Text fallback fine.
  - Run raw: rtk proxy bundle exec rspec ...
  - Force JSON: bin/rspec --format json ... (RTK parse success)
  - File RTK bug: formatter autodetect should skip JSON parse when --format not json.