src: create task runner PATH when missing

[Archkon]

Track whether the inherited environment contains PATH and create it from the discovered node_modules/.bin paths when absent.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.27%. Comparing base (a4aa3c0) to head (0bf4a6f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #64908      +/-   ##
==========================================
- Coverage   90.28%   90.27%   -0.01%     
==========================================
  Files         760      760              
  Lines      247061   247066       +5     
  Branches    46592    46595       +3     
==========================================
- Hits       223058   223039      -19     
+ Misses      15491    15489       -2     
- Partials     8512     8538      +26     

Files with missing lines	Coverage Δ
src/node_task_runner.cc	89.61% <100.00%> (+0.29%)	⬆️

... and 33 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.