feat: implement batch operations across contracts for gas optimization

[WillNovus]

Closes #38

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Implemented Batch Operations

Implemented batch operations across 5 core contracts and updated the shared library to reduce transaction costs and improve efficiency.

Shared Library Updates

• Added BatchResult type to track total, successful, and failed operations
• Set MAX_BATCH_SIZE to 20 to safeguard against resource limits
• Introduced BatchLimitExceeded and BatchEmpty error variants
• Defined BATCH_COMPLETED and BATCH_ITEM_FAILED event symbols

Contract Enhancements

Contract	Added Methods
Escrow	batch_create_milestones and batch_vote_milestones
Governance	batch_vote
Reputation	batch_update_scores and batch_award_badges
Project Launch	batch_contribute
Profit Distribution	batch_claim_dividends

Implementation Strategy

• Partial Failure Handling: Batches skip invalid items and return a summary result instead of reverting the whole transaction
• Gas Optimization: Performs require_auth() once per batch, significantly reducing auth overhead
• Robustness: Each item is individually validated to maintain contract integrity

[WillNovus]

@gabito1451 please review.

[gabito1451]

@WillNovus pleas look in to the failed tests

[gabito1451]

@WillNovus

[WillNovus]

It has been resolved.