feat(attestations): add domain separation to signature verification

[mariuszzak]

Description

Adds domain separation to attestation signature verification to prevent cross-protocol signature replay. The signing input changes from sha256(data) to sha256(type_tag || sha256(data)) where State=0x01 and Packet=0x02, ensuring signatures for state updates and packet proofs are not interchangeable.

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• Linked to GitHub issue with discussion and accepted design, OR link to spec that describes this work.
• Include changelog entry when appropriate (e.g. chores should be omitted from changelog).
• Wrote unit and integration tests if relevant.
• Updated documentation (docs/) if anything is changed.
• Added godoc comments if relevant.
• Self-reviewed Files changed in the GitHub PR explorer.
• Provide a conventional commit message to follow the repository standards.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.59%. Comparing base (eb52d21) to head (0ded97d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8799      +/-   ##
==========================================
+ Coverage   66.56%   66.59%   +0.03%     
==========================================
  Files         326      326              
  Lines       17106    17112       +6     
==========================================
+ Hits        11386    11396      +10     
+ Misses       5024     5022       -2     
+ Partials      696      694       -2     

Flag	Coverage Δ
08-wasm	64.81% <ø> (ø)
ibc-go	66.65% <100.00%> (+0.03%)	⬆️

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[srdtrk]

lgtm