closes #77

Implements minimal multi-bridge liquidity monitoring in the UI SDK to improve route reliability and visibility.

• Adds standardized liquidity model and monitoring layer (BridgeLiquidity, provider querying, structured errors, cache fallback)
• Introduces SSR-safe useBridgeLiquidity() with manual refresh and optional polling
• Integrates liquidity into BridgeCompare:
  • prioritizes high-liquidity routes
  • warns on low-liquidity routes
  • disables route selection when liquidity is insufficient
• Integrates liquidity alerts into status UI via BridgeStatus alias (TransactionHeartbeat)
• Exposes new exports for hook/utilities/components from @bridgewise/ui-components
• Adds unit tests for liquidity monitor fallback/prioritization and hook snapshot helper
• Updates README docs with usage examples, integration notes, and fallback/error behavior