Resolve issues #566, #572, #573, and #582: refactor ContractError, ad…

[Feyisara2108]

Closes #582
Closes #573
Closes #572
Closes #566

PR Summary:

What changed

• Updated README to match the current EscrowData implementation and documented the Payee structure with the multi-payee flow. (Closes README data structures show obsolete seller field instead of payees #582)
• Added comprehensive tests covering appeal_count behavior, including overflow boundary conditions or maximum-cap behavior as appropriate. (Closes appeal_dispute max appeal_count overflow not tested #573)
• Added dedicated tests covering create_escrow_with_fallback, dispute escalation, fallback resolution, and timing logic. (Closes create_escrow_with_fallback has no dedicated test #572)
• Introduced specific contract error variants to replace overloaded InvalidAmount usage, updated affected code paths, updated tests, and documented error codes. (Closes InvalidAmount error overloaded for 15+ distinct failure modes #566)

[drips-wave]

@Feyisara2108 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits