fix(giga): finalize state on failed transactions for V2 compatibility

[pdrobnjak]

Summary

• When ExecuteTransaction() failed (e.g., intrinsic gas errors), Giga returned early without calling Finalize(), so fee deductions from BuyGas() were never committed and the nonce was never incremented
• This diverged from V2 which always persists fees and nonce via ante handlers, even when execution fails
• Fix: on execution failure, increment the nonce and call Finalize() to commit state changes, matching V2 behavior

Test plan

• Run Giga state tests for stEIP1559 category to verify balance mismatches are resolved
• Verify failed transactions correctly deduct fees and increment nonce in both V2 and Giga modes
• Run existing unit tests to confirm no regressions

🤖 Generated with Claude Code

[github-actions]

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Feb 10, 2026, 3:19 PM

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.77%. Comparing base (28bc1c0) to head (09e331e).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
app/app.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2829      +/-   ##
==========================================
- Coverage   56.77%   56.77%   -0.01%     
==========================================
  Files        2070     2070              
  Lines      168274   168283       +9     
==========================================
  Hits        95542    95542              
- Misses      64247    64257      +10     
+ Partials     8485     8484       -1     

Flag	Coverage Δ
sei-chain	40.84% <0.00%> (-0.02%)	⬇️
sei-cosmos	48.13% <ø> (+<0.01%)	⬆️
sei-db	68.72% <ø> (ø)
sei-tendermint	58.76% <ø> (+0.05%)	⬆️

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Files with missing lines	Coverage Δ
app/app.go	65.76% <0.00%> (-0.10%)	⬇️

... and 28 files with indirect coverage changes

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