feat(autobahn): deploy native multi-host AWS clusters

[codchen]

Summary

• replace the single-EC2 Docker AWS topology with four EC2 instances, one validator per host
• build the selected seid revision natively on every instance and run it through systemd
• generate a shared genesis and Autobahn configuration on node 0, then distribute one node home to each host
• track per-node instance IDs plus public and private addresses for list, forward, and teardown
• allow ARM64 or AMD64 Ubuntu AMI resolution and configure GOMAXPROCS and GOGC
• retain teardown and inspection compatibility for state created by the legacy single-host deployer

This branch is based directly on main and intentionally contains no executor or throughput changes from #4087.

Validation

• go test -race ./cmd/autobahn-e2e -count=1
• go vet ./cmd/autobahn-e2e
• bash -n integration_test/autobahn/scripts/*.sh
• go build -o /tmp/autobahn-e2e-native ./cmd/autobahn-e2e
• native configuration-generation smoke test on an Ubuntu c8i.48xlarge: four validator keys, gentxs, node archives, a four-validator Autobahn file, and three persistent peers per node were generated successfully
• gofmt, goimports, and git diff --check

A fresh end-to-end provision is still pending because the locally configured AWS sessions are expired. The existing four-host native cluster was created with the same topology and systemd settings, but before this automation was checked in.

[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	Sep 3, 2026, 5:42 AM

[codecov]

Codecov Report

❌ Patch coverage is 69.64286% with 85 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.25%. Comparing base (2e256b5) to head (6cf2f72).

Files with missing lines	Patch %	Lines
cmd/autobahn-e2e/aws.go	72.22%	31 Missing and 24 partials ⚠️
cmd/autobahn-e2e/list.go	71.73%	9 Missing and 4 partials ⚠️
cmd/autobahn-e2e/teardown.go	42.10%	5 Missing and 6 partials ⚠️
cmd/autobahn-e2e/deploy.go	0.00%	4 Missing ⚠️
cmd/autobahn-e2e/forward.go	60.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4090      +/-   ##
==========================================
- Coverage   61.30%   60.25%   -1.06%     
==========================================
  Files        2178     2070     -108     
  Lines      190826   178489   -12337     
==========================================
- Hits       116990   107548    -9442     
+ Misses      62807    60932    -1875     
+ Partials    11029    10009    -1020     

Flag	Coverage Δ
sei-chain-pr	41.59% <69.64%> (?)
sei-db	69.80% <ø> (ø)
sei-db-state-db	?

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

Files with missing lines	Coverage Δ
cmd/autobahn-e2e/state.go	52.52% <100.00%> (+4.17%)	⬆️
cmd/autobahn-e2e/forward.go	20.48% <60.00%> (+0.48%)	⬆️
cmd/autobahn-e2e/deploy.go	4.23% <0.00%> (-0.12%)	⬇️
cmd/autobahn-e2e/teardown.go	31.94% <42.10%> (+6.52%)	⬆️
cmd/autobahn-e2e/list.go	42.85% <71.73%> (+9.52%)	⬆️
cmd/autobahn-e2e/aws.go	58.01% <72.22%> (+5.00%)	⬆️

... and 108 files with indirect coverage changes

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