Update networks and SDK constructor

[tolgahan-arikan]

Summary

• rename the public constructor inputs to publicApiKey and required projectId
• add the exported Networks registry with supported network metadata and lookup helpers
• update wallet/indexer usage, tests, type tests, docs, and examples for the new public API
• prepare the package metadata and GitHub Pages env wiring for alpha release setup

Verification

• pnpm exec tsc --noEmit
• pnpm test
• pnpm build
• pnpm build:node-example
• pnpm build:example
• pnpm publish --dry-run --no-git-checks