fix: nested options have invalid environment variable names

[phm07]

Nested options' environment variables contained dots which made them invalid.

---

Since there are no nested options yet, this fix should not appear in the changelog.

BEGIN_COMMIT_OVERRIDE
chore: nested options have invalid environment variable names
END_COMMIT_OVERRIDE

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 59.78%. Comparing base (c0cb16b) to head (db86e82).
Report is 3 commits behind head on main.

Files	Patch %	Lines
internal/state/config/config.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #799      +/-   ##
==========================================
+ Coverage   59.68%   59.78%   +0.10%     
==========================================
  Files         210      210              
  Lines        7639     7641       +2     
==========================================
+ Hits         4559     4568       +9     
+ Misses       2437     2430       -7     
  Partials      643      643              

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