Fix 8 TypeScript compilation errors and add EIP712 runtime support

[sudo-owen]

Summary

This PR fixes 8 categories of TypeScript compilation errors in the Solidity transpiler, reducing errors from 39 to 23. It also adds EIP712 runtime support for contracts using typed structured data hashing, and refactors the runtime module structure to avoid circular dependencies.

Key Changes

TypeScript Compilation Fixes (Batch 2)

• Array .length to BigInt: Wraps array .length property in BigInt() when assigned to bigint variables, excluding EnumerableSetLib types that already return bigint
• address(uint160(...)) Pattern: Converts bigint to hex address strings using `0x${(expr).toString(16).padStart(40, "0")}`
• Interface Casts with Method Calls: Casts interface patterns like ICPU(address(this)).calculateMove() to any to allow method calls
• new string(length) Pattern: Transpiles Solidity's new string(length) to empty string "" and handles new bytes(length)
• bytes32("STRING") Conversion: Properly converts string literals cast to bytes32 to hex encoding
• Override Modifier on Interface Methods: Excludes interface methods from get_all_inherited_methods() to prevent false override errors
• bytes32 Constants as Hex Strings: Generates string values instead of BigInt for bytes32 hex literals
• ABI Type Inference for address() Casts: Infers address(this) in abi.encode as 'address' type instead of 'uint256'

EIP712 Runtime Support

• Added new EIP712.ts runtime module with full EIP-712 typed data hashing implementation
• Includes domain separator computation, typed data hashing, and EIP-5267 support
• Added EIP712 configuration to runtime-replacements.json with mixin support for multiple inheritance
• Supports both static and dynamic domain name/version via _domainNameAndVersionMayChange()

Runtime Module Refactoring

• Created new base.ts module containing core Contract class and utilities
• Moved Storage, EventStream, ContractAddressRegistry, and ADDRESS_ZERO to base.ts
• Updated runtime modules (Ownable, ECDSA, EnumerableSetLib) to import from ./base instead of ./index
• Prevents circular dependency issues when runtime replacements extend Contract

Ownable Mixin Support

• Added mixin field to Ownable configuration in runtime-replacements.json
• Enables multiple inheritance pattern for contracts extending both a primary class and Ownable

Dependencies

• Added vitest (^4.0.18) to dev dependencies for testing

Remaining Issues

Reduced from 39 to 23 errors. Main categories still needing fixes:

1. Missing EIP712 module (now partially addressed with runtime implementation)
2. Multiple inheritance with Ownable/EIP712 (requires mixin patterns)
3. Struct field type inference in abi.encode
4. viem type casting for 0x${string} addresses
5. Record vs Map return type mismatches

Testing

The changes maintain backward compatibility with existing transpiled code while fixing specific TypeScript compilation patterns identified in the codebase.

https://claude.ai/code/session_01Q76KPUo9pMEzA4YARpnPw1