refactor: using stdlib instead of envsubst for variable substitution

[hugoh]

No description provided.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[deepsource-io]

DeepSource Code Review

We reviewed changes in 57456b1...f260693 on this pull request. Below is the summary for the review, and you can see the individual issues we found as inline review comments.

See full review on DeepSource ↗

PR Report Card

Overall Grade

Security   Reliability   Complexity   Hygiene

Code Review Summary

Analyzer	Status	Updated (UTC)	Details
Go		Apr 26, 2026 7:18p.m.	Review ↗
Secrets		Apr 26, 2026 7:18p.m.	Review ↗

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Important

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.26%. Comparing base (57456b1) to head (f260693).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #242      +/-   ##
==========================================
+ Coverage   87.88%   89.26%   +1.38%     
==========================================
  Files          18       18              
  Lines         949      736     -213     
==========================================
- Hits          834      657     -177     
+ Misses         86       51      -35     
+ Partials       29       28       -1     

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