Feature/aip 002 AI price suggestion for voyage pricing

[michal-bakshi]

PR: AI Price Suggestion for Voyage Pricing

Adds a GET /voyages/{voyageId}/price-suggestion?containerSize=... endpoint that returns an AI-generated USD price range, confidence level (HIGH/MEDIUM/LOW), reasoning, and optional historical stats (avg/min/max).

Key Changes

• AI clients — completeWithSchema implemented in ClaudeAiClient, OpenAiClient, and NoOpAiClient for structured JSON output
• Historical data — same-route lookup via VoyagePriceRepository; fallback to similar routes via CountryRegionMapper + PortRepository
• Schema validation — networknt json-schema-validator validates LLM output; schema built by PriceSuggestionSchemaBuilder from price-suggestion.json
• Fallback — returns confidence=LOW with a message on missing data or AI failure
• New repository methods — countByVoyageIds, findHistoricalPricesSameRoute, findHistoricalPricesSimilarRoute, findByCountryIn

Tests

• VoyagePriceSuggestionControllerTest — integration tests via MockMvc covering: suggestion with historical stats, fallback to confidence=LOW when no data, 404 for unknown voyage, and correct response for FORTY_FOOT.

• PriceSuggestionSchemaTest validates the schema itself — covers valid payloads, missing required fields, wrong confidence type, invalid enum value, and extra properties.

Verified

mvn clean verify
mvn fmt:check

Close #48