refactor(ci): pin genparams checkout to image commit

[purusang]

Description

Pins the ci-genparams.yml checkout to the commit that produced the selected strata-datatool image by default. This keeps the params generation script, templates, chainspec, and datatool image aligned for a given image tag.

Manual runs can still pass checkout_ref to test workflow changes from a branch against an existing datatool image tag.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature/Enhancement (non-breaking change which adds functionality or enhances an existing one)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Refactor
• New or updated tests
• Dependency Update

Notes to Reviewers

The default path avoids commit drift: when checkout_ref is omitted, actions/checkout uses the full SHA behind the selected datatool image tag. The override exists only for manual workflow debugging.

Is this PR addressing any specification, design doc or external reference document?

• Yes
• No

If yes, please add relevant links:

Checklist

• I have performed a self-review of my code.
• I have commented my code where necessary.
• I have updated the documentation if needed.
• My changes do not introduce new warnings.
• I have added (where necessary) tests that prove my changes are effective or that my feature works.
• New and existing tests pass with my changes.
• I have disclosed my use of AI in the body of this PR.

Validation:

• git diff --check
• actionlint .github/workflows/ci-genparams.yml

AI assistance notice: This PR was prepared with AI assistance.

Related Issues

N/A

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 4de75962a5

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[github-actions]

Commit: eefdc6d

SP1 Execution Results

program	cycles	gas
EVM EE Chunk	824,732	969,394
EVM EE Account	404,056	498,593
Checkpoint	2,601,550	3,007,194

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.42%. Comparing base (b5d34b8) to head (4de7596).
⚠️ Report is 1 commits behind head on main.

@@            Coverage Diff             @@
##             main    #1946      +/-   ##
==========================================
- Coverage   84.42%   84.42%   -0.01%     
==========================================
  Files         637      637              
  Lines       76805    76805              
==========================================
- Hits        64840    64839       -1     
- Misses      11965    11966       +1     

Flag	Coverage Δ
functional	66.50% <ø> (-0.01%)	⬇️
unit	69.52% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.
see 1 file with indirect coverage changes

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[storopoli]

ACK 4de7596

I don't understand the codex P2 finding, please take a look.