Add WASM32-WASIP2 target support for WebAssembly deployment

[avrabe]

Summary

Add comprehensive support for the wasm32-wasip2 target to enable deployment of MCP servers as WebAssembly components with full system interface access.

Background

WASI Preview 2 provides much more system capability than basic WASM, including:

• File I/O through WASI filesystem interfaces
• Networking through WASI sockets
• CLI interfaces through WASI command-line tools
• Standard library compatibility via rustix/wstd

Implementation Tasks

Core Compilation Support

• Add wasm32-wasip2 to supported targets in Cargo.toml workspace
• Add conditional compilation features for WASM-specific code paths
• Update dependency versions to ensure WASM compatibility
• Test core protocol functionality on WASM target

Dependency Audit & Updates

• Audit all dependencies for wasm32-wasip2 compatibility
• Replace or feature-gate incompatible dependencies:
  • tokio - use WASM-compatible async runtime or feature flags
  • Platform-specific file operations in mcp-auth
  • Network binding operations
• Add WASM-specific alternatives where needed

Runtime Adaptations

• Adapt async runtime selection for WASM contexts
• Update file I/O patterns to use WASI interfaces
• Modify networking code for WASM socket capabilities
• Ensure thread-local storage compatibility

Build System Integration

• Create WASM-specific Cargo features
• Add build scripts for WASM optimization
• Integration with rules_wasm_component (separate issue)

Acceptance Criteria

• All core crates compile successfully for wasm32-wasip2
• Basic MCP protocol tests pass in WASM context
• Example MCP server runs as WASM component
• Documentation for WASM development workflow
• CI/CD pipeline includes WASM target testing

Related Issues

• Bazel Build System Integration (#TBD)
• WASM Development Workflow (#TBD)
• Transport Layer WASM Compatibility (#TBD)

References

• WASI Preview 2 Specification
• Rust WASM Book
• wasm32-wasip2 Target Documentation