fix(compiler): prevent same-name stages in pipeline configs

[ecrupper]

If two stages have the same name and they are run at the same time, it can result in a panic for trying to close a closed channel

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.09%. Comparing base (6bdd986) to head (38c9eda).
⚠️ Report is 1 commits behind head on main.

❌ Your project status has failed because the head coverage (58.09%) is below the target coverage (90.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1360   +/-   ##
=======================================
  Coverage   58.08%   58.09%           
=======================================
  Files         634      634           
  Lines       24573    24577    +4     
=======================================
+ Hits        14274    14278    +4     
  Misses       9651     9651           
  Partials      648      648           

Files with missing lines	Coverage Δ
compiler/native/validate.go	100.00% <100.00%> (ø)

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