Export ProposerPriorityHash metric for divergence monitoring

[wen-coding]

Summary

• Add two Prometheus gauges exported every 1024 heights to let operators detect ProposerPriority divergence between validators
• tendermint_state_proposer_priority_hash: first 6 bytes of the hash packed into a float64 (48 bits fits in the float64 mantissa; constant cardinality of one series per node)
• tendermint_state_proposer_priority_hash_height: paired height so operators correlate samples taken at the same checkpoint
• Log line at each checkpoint carries the full 32-byte hex hash plus the packed value for grep-based debugging

Test plan

• go vet ./sei-tendermint/internal/state/... passes
• go test ./sei-tendermint/internal/state passes
• New test TestApplyBlockProposerPriorityHash applies 1024 real blocks and verifies exactly one emission at the interval boundary, with the correct packed hash and height values

[github-actions]

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Apr 21, 2026, 1:20 AM

[codecov]

Codecov Report

❌ Patch coverage is 65.71429% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.31%. Comparing base (a3bb4e8) to head (85388ae).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
sei-tendermint/internal/state/metrics.gen.go	50.00%	12 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3277   +/-   ##
=======================================
  Coverage   59.31%   59.31%           
=======================================
  Files        2071     2071           
  Lines      169866   169891   +25     
=======================================
+ Hits       100755   100770   +15     
- Misses      60335    60346   +11     
+ Partials     8776     8775    -1     

Flag	Coverage Δ
sei-chain-pr	68.47% <65.71%> (?)
sei-db	70.41% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-tendermint/internal/state/execution.go	80.67% <100.00%> (+1.02%)	⬆️
sei-tendermint/internal/state/metrics.gen.go	14.43% <50.00%> (-0.03%)	⬇️

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