Implement contract error code documentation

[El-swaggerito]

Description

Difficulty: Hard

Type: Documentation

Summary

Document contract error codes and failure reasons.

Current Behaviour

Contract failures may be difficult for SDK and mobile consumers to interpret.

Expected Behaviour

The contracts repo should document expected errors for deposits, withdrawals, locks, balances, initialisation, and authorisation.

Suggested Implementation

Create error documentation, map errors to user-facing meanings, and link from README.

Files or Areas Likely Affected

• docs/
• README.md
• contracts/
• src/
• tests/

Acceptance Criteria

• Contract error code documentation is added.
• Deposit errors are documented.
• Withdrawal errors are documented.
• Lock and balance errors are documented.
• Authorisation errors are documented.
• README links to error documentation.

Additional Notes

This supports SDK and mobile integration.

[Ridioortv]

lo puedo hacer

[devkryssie]

HI, MAINTAINER I WOULD LIKE TO WORK ON THIS ISSUE AND SUBMIT PR BEFORE 24HOURS