feat: implement bridge reliability service with event recording and r…

[Xaxxoo]

…eliability calculation

• Add BridgeReliabilityService for managing bridge transaction events and calculating reliability metrics.
• Introduce BridgeTransactionEvent entity to store transaction outcomes and related data.
• Create ReliabilityCalculatorService for computing reliability scores and tiers based on transaction data.
• Implement DTOs for recording events and querying reliability metrics.
• Add enums for transaction outcomes and reliability tiers.
• Establish constants for reliability thresholds and scoring.
• Write unit tests for service methods to ensure correct functionality and reliability calculations.

Closes #54