Add release/v6.4

[philipsu522]

Describe your changes and provide context

1. CHANGELOG.md — Added a new ## v6.4 section at the top with 130 entries covering all substantive changes since v6.3.0,
   including:

• New features (FlatKV store, Giga executor, Autobahn consensus, Parquet receipt store, composite state store, etc.)
• Bug fixes (consensus, EVM, store, p2p, giga, flatkv)
• Performance improvements (lazy-init stores, parallelized DB commits, etc.)
• Module consolidation (sei-cosmos, sei-tendermint, sei-wasmd, sei-ibc-go, sei-db, sei-wasmvm all flattened into sei-chain)

2. scripts/bump-version.sh — Fixed a bug where evm_events.go was referenced by sed but never copied to the legacy target
   directory. Changed the copy block to iterate over both precompiles.go and evm_events.go.

3. scripts/bump-version.sh v6.4.0 v6.3.3 — Successfully ran, which:

• Generated updated setup.go for all 13 precompile modules
• Created precompiles/common/legacy/v640/ with both precompiles.go and evm_events.go (package v640)
• Copied all 13 precompile modules to their respective legacy/v640/ directories with updated imports pointing to
  common/legacy/v640
• Appended v6.4.0 to app/tags

Testing performed to validate your change

[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	Mar 12, 2026, 4:38 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.25%. Comparing base (2f6c4e5) to head (74c4e17).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3060      +/-   ##
==========================================
- Coverage   58.27%   58.25%   -0.02%     
==========================================
  Files        2076     2076              
  Lines      171480   171493      +13     
==========================================
- Hits        99933    99910      -23     
- Misses      62615    62635      +20     
- Partials     8932     8948      +16     

Flag	Coverage Δ
sei-chain	58.22% <100.00%> (-0.02%)	⬇️
sei-chain-pr	69.72% <100.00%> (?)
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
precompiles/addr/setup.go	90.00% <100.00%> (+0.52%)	⬆️
precompiles/bank/setup.go	90.00% <100.00%> (+0.52%)	⬆️
precompiles/distribution/setup.go	88.23% <100.00%> (+0.73%)	⬆️
precompiles/gov/setup.go	88.23% <100.00%> (+0.73%)	⬆️
precompiles/ibc/setup.go	89.47% <100.00%> (+0.58%)	⬆️
precompiles/json/setup.go	88.23% <100.00%> (+0.73%)	⬆️
precompiles/oracle/setup.go	89.47% <100.00%> (+0.58%)	⬆️
precompiles/p256/setup.go	81.81% <100.00%> (+1.81%)	⬆️
precompiles/pointer/setup.go	89.47% <100.00%> (+0.58%)	⬆️
precompiles/pointerview/setup.go	87.50% <100.00%> (+0.83%)	⬆️
... and 3 more

... and 25 files with indirect coverage changes

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