feat(contract): integrate comprehensive soroban events for indexing

[ayomideadeniran]

This PR adds core escrow logic and emits structured Soroban events to enable real-time indexing for Vaultix.

Changes

• Implemented escrow flows: create_escrow, confirm_delivery, raise_dispute, resolve_dispute
• Added Soroban events for all state changes (create, release, dispute, resolve)
• Added get_escrow helper for state verification
• Added tests validating logic and event emission
• Fixed Soroban SDK and Rust compatibility issues

Impact

• Enables real-time UI updates via off-chain indexing
• Keeps frontend in sync with on-chain state

Verification

• cargo test passed

Closes #38

[Cedarich]

Please check formating run cargo fmt --all -- --check and address errors

[ayomideadeniran]

@Cedarich Kindly check it out now

[Cedarich]

please Run cargo clippy --all-targets --all-features -- -D warnings and address errors

[ayomideadeniran]

@Cedarich I will do that now

[ayomideadeniran]

@Cedarich Done you can now check it out.

[ayomideadeniran]

@Cedarich Done you can now check it out.

[Cedarich]

please address conflicts

[Cedarich]

Please address formatting errors

[ayomideadeniran]

@Cedarich Kindly check i just finish resolving the conflict.

[ayomideadeniran]

@Cedarich i just finish addressing formatting errors.

[ayomideadeniran]

@Cedarich Do i really do a great work ? Or i need to improve ? If so i need your compliment points so i can know where my strength lies.

[ayomideadeniran]

@Cedarich I deserve compliments more kindly consider