evmrpc: remove /block_results dependencies from block trace, sei_getCosmosTx, getHeader (CON-256)

[wen-coding]

Summary

Three eth-side block-scoped RPC paths leaned on /block_results data that isn't populated under Autobahn — they returned empty (or wrong) results regardless of block contents.

• Block trace backend (debug_traceBlockBy*, sei_traceBlockBy*ExcludeTraceFail) now iterates the block's own tx list.
• sei_getCosmosTx looks up the cosmos hash directly via receipt.TransactionIndex, no iteration needed.
• getHeader (trace path's eth-block construction) sources gasLimit from sdkCtx.ConsensusParams(), matching the block.go:489-491 pattern already used by eth_getBlockByNumber. Under legacy this also fixes a latent silent fallback to DefaultBlockGasLimit.

Existing .iox fixtures only asserted response kind, so empty results / early-exit error paths looked indistinguishable from the fix; the trace fixtures now bind to the seeded deploy block and assert non-empty output, and a positive-case getCosmosTx-deploy.iox was added.

Test plan

• go test ./evmrpc/ (22.3s)
• go test ./evmrpc/tests/ (27.7s)
• Full RPC IO suite, docker localnet, Autobahn cluster: 161/161
• Full RPC IO suite, docker localnet, legacy cluster: 160/160 (run on the earlier 5-fixture state; new fixture additive)
• Buggy binary (block-trace fix reverted) on Autobahn: 156/160 — exactly the four updated trace fixtures fail
• Buggy binary (sei_getCosmosTx fix reverted) on Autobahn: 160/161 — exactly the new getCosmosTx-deploy.iox fixture fails
• gofmt -s -l clean

[cursor]

PR Summary

Medium Risk
Changes block tracing, sei_getCosmosTx, and header construction logic to avoid /block_results, which can affect correctness of RPC outputs across consensus engines. Risk is moderate due to altered indexing/receipt-based lookups and gas limit derivation impacting downstream clients and tests.

Overview
Fixes block-scoped RPC behavior under Autobahn by removing reliance on Tendermint /block_results data in multiple paths.

debug_traceBlockBy*/sei_traceBlockBy*ExcludeTraceFail now iterate tmBlock.Block.Txs directly, sei_getCosmosTx derives the Cosmos tx hash via the receipt’s TransactionIndex (with bounds checking), and getHeader sources GasLimit from sdkCtx.ConsensusParams() with a default fallback.

Updates unit tests to reflect the new gas-limit source and rewrites RPC IO fixtures to bind trace targets from a seeded deploy receipt and assert non-empty trace output; adds a positive-case fixture for sei_getCosmosTx.

^{Reviewed by Cursor Bugbot for commit 0d2b1cb. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 19, 2026, 10:02 PM

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The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	May 16, 2026, 10:28 PM

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.36%. Comparing base (80a4364) to head (0d2b1cb).

Files with missing lines	Patch %	Lines
evmrpc/association.go	50.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3452      +/-   ##
==========================================
+ Coverage   59.05%   59.36%   +0.30%     
==========================================
  Files        2188     2111      -77     
  Lines      182088   173431    -8657     
==========================================
- Hits       107530   102953    -4577     
+ Misses      64925    61588    -3337     
+ Partials     9633     8890     -743     

Flag	Coverage Δ
sei-chain-pr	66.93% <75.00%> (?)
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
evmrpc/simulate.go	74.78% <100.00%> (+0.59%)	⬆️
evmrpc/association.go	40.19% <50.00%> (-4.35%)	⬇️

... and 226 files with indirect coverage changes

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[amir-deris]

While we are here, receipt seems to be redundant alias and can be removed.

[wen-coding]

removed

[amir-deris]

Would tenderminttypes be a better alias name?

[wen-coding]

changed