sui-graphql-rust-sdk: add dynamic fields API [11/n]

[tpham-mysten]

Summary

Add get_dynamic_fields(parent) method to list dynamic fields with their values as a paginated stream.

• DynamicFieldEntry: struct with name (JSON), name_type, value (JSON), and field_type
• Uses GraphQL nested queries to fetch both name and value in one request
• Returns impl Stream<Item = Result<DynamicFieldEntry, Error>> with automatic pagination

Testing

• cargo nextest run -p sui-graphql
• Run the API locally to test

Stack

• sui-graphql-rust-sdk: add basic GraphQL client with partial error handling [1/n] #191
• sui-graphql-rust-sdk: add QueryResponse derive macro for field extraction [2/n] #194
• sui-graphql-rust-sdk: add array extraction support to QueryResponse macro [3/n] #195
• sui-graphql-rust-sdk: add compile-time schema validation to QueryResponse macro [4/n] #196
• sui-graphql-rust-sdk: add field suggestions for validation errors [5/n] #197
• sui-graphql-rust-sdk: add pagination support and object methods [6/n] #198
• sui-graphql-rust-sdk: add coin balance methods [7/n] #199
• sui-graphql-rust-sdk: add chain info methods with alias support [8/n] #200
• sui-graphql-rust-sdk: add transaction fetching API [9/n] #205
• sui-graphql-rust-sdk: add checkpoint fetching API [10/n] #206
• sui-graphql-rust-sdk: add dynamic fields API [11/n] #207 ⬅️