Improve the explanation of context in frontend.mdx and backend.mdx

The concept of 'context' in Reclaim Protocol is crucial but could be explained more clearly and comprehensively in both the frontend.mdx and backend.mdx files.

Tasks:

1. In both files, expand the section on context to include:
   • A clear definition of what 'context' means in Reclaim Protocol
   • The importance of context in securing proofs and preventing misuse
   • Detailed explanation of the 'address' and 'message' components of context
2. Add more diverse examples of how context can be used effectively:
   • Example for a blockchain application using the address field
   • Example for a web application using the message field for freshness
   • Example combining both address and message for maximum security
3. Include best practices for generating and verifying context
4. Add a section on common pitfalls or misunderstandings about context
5. Provide code snippets demonstrating how to add, retrieve, and verify context in both frontend and backend implementations
6. Include a troubleshooting section for context-related issues

Enhancing this explanation will help developers better understand and utilize the context feature, improving the security and specificity of their Reclaim Protocol implementations.

Contributors: Please note that by submitting a pull request, you are agreeing to accept and sign the Contributor License Agreement (CLA) found at https://github.com/reclaimprotocol/.github/blob/main/CLA.md

Start by reading the existing context sections in frontend.mdx and backend.mdx and compare how each implementation currently explains context. Expand both files with the requested definitions, examples, best practices, pitfalls, code snippets, and troubleshooting guidance. Done means both pages comprehensively cover adding, retrieving, and verifying context for frontend and backend users.