This commit introduces a new documentation file for the Mina Signer library. The documentation covers installation, usage, and examples for the library. It aims to provide developers with a comprehensive guide to integrating Mina Signer into their projects.

… navigation and user experience

feat(mina-signer.mdx): add nonce field to payment object to ensure uniqueness of transactions

…o1js

This commit adds a comprehensive guide on how to use Mina Signer with o1js for signing and verifying zkApp transactions. It includes a code snippet demonstrating the process and a tip advising when to use Mina Signer over o1js. This update is intended to provide better guidance for developers integrating Mina Signer into their projects.

This commit adds a new section to the Mina Signer documentation explaining how to sign and verify Field payloads. This is useful for developers who want to ensure their payloads have not been tampered with. The section includes code examples and notes on handling Field types from different libraries.

…rehensive documentation on zkApp transactions, explaining their purpose and usage with an example code snippet.

1. Specify that the installation command is for Mina Signer for better context.
2. Remove the definite article before Mina Signer for consistency.
3. Add explanation for the need to specify the network during Mina Signer initialization.
4. Move the default network information to a tip box for better visibility.
5. Specify that Mina Signer supports signing and verifying of arbitrary Field payloads for better understanding.

…rove clarity

1. Replace 'keys' with 'keypairs' for more accurate terminology.
2. Add information about broadcasting signed payments or delegations to the network via the Mina Daemon.
3. Add hyperlink to 'o1js' for better navigation and understanding.
4. Modify description of Mina Signer's integration with 'o1js' to include signing/verifying Field payloads.
5. Clarify that Mina Signer can sign a zkApp transaction that can easily be broadcasted with a Mina Daemon.
6. Remove 'Examples' section as it seems to be empty and unnecessary.

…f summary of the Mina Signer library to provide a clear and concise overview of the library's purpose and functionality

…tation

- Reworded several sentences for better readability and clarity.
- Organized the features of Mina Signer into a list for easier understanding.
- Made the instructions for specifying the network more explicit.
- Changed the headers to use '&' instead of '/' for consistency.
- Expanded on the explanation of nullifiers for better understanding.
- Made the instructions for generating a nullifier more explicit.

… readability

The backticks were removed from o1js to maintain consistency throughout the document and improve readability. The backticks are typically used for code snippets or commands, not for naming libraries or tools.