fix: Expose underlying timestamp assertion support

[mauricefisher64]

Changes in this pull request

This exposes the generation of the timestamp assertion to the upper levels of the API.

Checklist

• This PR represents a single feature, fix, or change.
• All applicable changes have been documented.
• Any TO DO items (or similar) have been entered as GitHub issues and the link to that issue has been included in a comment.

[codecov]

Codecov Report

❌ Patch coverage is 31.48148% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.35%. Comparing base (aae8b05) to head (9db3cf1).

Files with missing lines	Patch %	Lines
sdk/src/store.rs	32.69%	35 Missing ⚠️
sdk/src/assertions/timestamp.rs	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1371      +/-   ##
==========================================
- Coverage   78.39%   78.35%   -0.04%     
==========================================
  Files         162      162              
  Lines       38771    38802      +31     
==========================================
+ Hits        30395    30404       +9     
- Misses       8376     8398      +22     

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[codspeed-hq]

CodSpeed Performance Report

Merging #1371 will not alter performance

_{Comparing expose_tsa (9db3cf1) with main (aae8b05)}

Summary

✅ 18 untouched benchmarks