Expose gRPC compression options

[Sushisource]

Summary

• expose gRPC compression as explicit discriminated option variants on NativeConnection
• keep gzip as the default while allowing grpcCompression: { codec: 'none' } to opt out
• model the public/native types so future variants can add variant-specific fields, e.g. { codec: 'zstd', level: 3 }, without adding level to gzip

Testing

• pnpm exec prettier --write packages/worker/src/connection-options.ts packages/core-bridge/ts/native.ts
• pnpm -C packages/worker run build
• pnpm -C packages/test run build:ts
• pnpm -C packages/test exec ava ./lib/test-native-connection.js --match='NativeConnection: gRPC compression*'