[FEATURE] ERC-165 Interface Registry for Identity Protocol

[anshulchikhale30-p]

Feature and its Use Cases

This feature adds basic ERC-165 interface support to the Identity protocol
so that other contracts and dApps can easily detect whether a deployed
contract supports Identity-related functionality.

By implementing the standard supportsInterface(bytes4) function, external
systems can safely check compatibility before interacting with Identity
contracts.

Use cases:

• Other smart contracts can verify IdentityToken support before calling it
• Frontends can detect Identity-compatible contracts dynamically
• Future Identity features can be added without breaking existing integrations

This is a small, non-breaking improvement that follows Ethereum best
practices and improves long-term composability.

Additional Context

This follows the ERC-165 standard and can be implemented incrementally,
starting with IdentityToken and extended to other Identity-related
interfaces as they are added.

Code of Conduct

• I have joined the Discord server and will post updates there
• I have searched existing issues to avoid duplicates

[anshulchikhale30-p]

Happy to take this up as a small PR if the approach looks good. thank you
@Zahnentferner @KanishkSogani