[Bug] Minor code quality issues (incorrect types, string throws, wrong package name in docs)

[marshacb]

• InputObject.type and InputObject.id use "string" literal instead of string type (sdk/src/models/input/inputObject.ts:11-12)
• String literals thrown instead of Error objects (create-leo-app/template-offline-public-transaction-ts/src/helpers.ts, e2e/testnet/index.js)
• Docs reference @provable.sdk instead of @provablehq/sdk (docs/examples/01_transfer_public.md, likely others)