feat: add EVM migration support and refactor tx building pipeline

[akobrin1]

Summary

Add EVM migration module support, refactor the transaction building pipeline into composable stages, and replace the local ethsecp256k1 implementation with the upstream cosmos/evm package.

Changes

EVM Migration Module

• New EVMigrationClient in blockchain/evmigration.go with query operations:
  • Params — current module parameters
  • MigrationRecord — lookup by legacy address
  • MigrationRecordByNewAddress — lookup by new address
  • MigrationEstimate — pre-flight migration estimate
  • MigrationStats — aggregate statistics
• Wired into blockchain.Client alongside existing Action/SuperNode/Claim modules

Transaction Building Refactor

• Introduced TxBuildOptions struct for fine-grained tx control:
  • Multi-message support (Messages []sdk.Msg)
  • Explicit AccountNumber/Sequence (skip on-chain query when provided)
  • GasLimit override & SkipSimulation flag
  • Custom FeeAmount
• Decomposed buildAndSignTx into composable stages:
  • PrepareTx — builds unsigned builder + resolves signer metadata
  • SignPreparedTx — signs a prepared builder with explicit signer info
  • BuildAndSignTxWithOptions — end-to-end convenience
• Added BroadcastAndWait for broadcast + wait-for-inclusion in a single call
• Existing BuildAndSignTx / BuildAndSignTxWithGasAdjustment delegate to new pipeline (backwards compatible)

Crypto / ethsecp256k1

• Removed local pkg/crypto/ethsecp256k1/ package
• Replaced with upstream github.com/cosmos/evm/crypto/ethsecp256k1
• Updated NewKeyring to use evmhd.EthSecp256k1Option() and evmcryptocodec.RegisterInterfaces
• Registered additional module interfaces in NewDefaultTxConfig (bank, staking, distribution, authz, claim, supernode) for proper encoding/decoding

Config & Defaults

• Moved applyConfigDefaults into base.New, applying MaxRecvMsgSize/MaxSendMsgSize (50 MB) defaults
• Consolidated WaitTx defaults application

Dependency Bumps

Package	Old	New
Go	1.25.5	1.26.1
cosmos-sdk	v0.53.5	v0.53.6
cometbft	v0.38.20	v0.38.21
gRPC	v1.77.0	v1.79.2
LumeraProtocol/lumera	v1.10.0	v1.11.0
cosmos/evm	—	v0.6.0 (new)

Cleanup

• Removed deprecated blockchain/messages.go
• Updated docs/DEVELOPER_GUIDE.md and .github/copilot-instructions.md for Go 1.26.1

Tests

• TestBuildAndSignTxWithOptions_ManualSignerInfo — offline signing with explicit account/sequence
• TestBuildAndSignTxWithOptions_QueriesAccountInfoAndSimulates — full pipeline with mock gRPC
• TestNewAppliesDefaultMessageSizes — validates config defaults

Note

Local replace directives for lumera and supernode are active for development. These should be commented out before merging/releasing.

[roomote-v0]

Rooviewer   See task

Reviewed the EVM migration module, tx building refactor, crypto/ethsecp256k1 replacement, and dependency bumps. Found 2 issues to address before merging.

• go.mod: Local replace directives for lumera and supernode are active (uncommented) -- this will break any consumer of the module. Comment them out before merging.
• blockchain/base/tx.go: int64(gas) cast in resolveFeeAmount can silently overflow for large uint64 gas values, now that GasLimit is user-controllable via TxBuildOptions.

_{Mention @roomote in a comment to request specific changes to this pull request or fix all unresolved issues.}

[roomote-v0]

The local replace directives are uncommented (active). As the PR description itself notes, these must be commented out before merging. With these active, any consumer running go get github.com/LumeraProtocol/sdk-go will fail because ../lumera and ../supernode don't exist on their machine. This is a merge blocker.

Suggested change

	github.com/LumeraProtocol/lumera => ../lumera
	github.com/LumeraProtocol/supernode/v2 => ../supernode
	// Local development - uncomment these for local testing
	// Comment these lines before releasing
	// github.com/LumeraProtocol/lumera => ../lumera
	// github.com/LumeraProtocol/supernode/v2 => ../supernode

_{Fix it with Roo Code or mention @roomote and request a fix.}

[roomote-v0]

int64(gas) silently wraps to a negative number when gas > math.MaxInt64. Now that GasLimit is directly user-controllable via TxBuildOptions, a caller passing a very large value (or a value computed from a large simulation result with a high adjustment factor) would produce an incorrect fee. Consider adding a bounds check or using sdkmath.NewIntFromUint64(gas) to avoid the cast.

Suggested change

	feeDec := c.config.GasPrice.MulInt64(int64(gas)).Ceil().TruncateInt()
	feeDec := c.config.GasPrice.MulInt(sdkmath.NewIntFromUint64(gas)).Ceil().TruncateInt()

_{Fix it with Roo Code or mention @roomote and request a fix.}