src,lib: handle invalid stdio configuration gracefully

[juanarbol]

Fixes an issue where malformed or unexpected stdio configurations could cause crashes or undefined behavior during child process spawning. This patch ensures robust validation of stdio entries:

Fixes: #55932

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I don't think we should patch user-space misconfiguration. This is a rare case and, could be extrapolated to different issues. I never faced an issue due to proto mutation. But I personally don't think we should patch that (except for the native layer.)

[codecov]

Codecov Report

Attention: Patch coverage is 69.23077% with 4 lines in your changes missing coverage. Please review.

Project coverage is 88.00%. Comparing base (f270462) to head (e079e6e).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/child_process.js	42.85%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #55942      +/-   ##
==========================================
- Coverage   88.49%   88.00%   -0.50%     
==========================================
  Files         653      653              
  Lines      187728   187741      +13     
  Branches    36182    35875     -307     
==========================================
- Hits       166136   165221     -915     
- Misses      14814    15700     +886     
- Partials     6778     6820      +42     

Files with missing lines	Coverage Δ
src/process_wrap.cc	84.81% <100.00%> (+0.49%)	⬆️
lib/internal/child_process.js	93.87% <42.85%> (-1.11%)	⬇️

... and 91 files with indirect coverage changes

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[jasnell]

In addition to the link, a short description of the issue being tested would be helpful so folks don't have to actually follow the link to see what this is about.