Add MethodPubkeys utility type to simplify account resolution in tests

[Neocryptoquant]

Currently, extracting the types for resolved account addresses (public keys) in integration tests requires verbose return type chaining.

Current boilerplate

let pubkeys: Awaited<
  ReturnType<
    ReturnType<typeof program["methods"]["myMethod"]>["rpcAndKeys"]
  >
>["pubkeys"];

Proposed Solution

Introduce a MethodPubkeys utility type in the TypeScript client.
This provides a better way to extract these types directly from the IDL instructions.

New Usage

let pubkeys: anchor.MethodPubkeys<MyIdl, "myMethod">;

Code Locations Affected

• ts/packages/anchor/src/program/namespace/types.ts
• ts/packages/anchor/src/program/namespace/index.ts