[codex] Use source tick batches inside Intrade

[LimiNode]

Summary

• parse BTC, FX, and polling payloads directly into events::TickUpdateBatch values
• carry source batches through BtcPriceManager, FxPriceWebSocketManager, and PriceManager without intermediate SingleTick wrappers
• keep
  equest_price() and typed PriceSnapshot as explicit compatibility adapters
• add regression coverage for /price_now, BTC, and FX parser metadata

Tests

• focused Intrade parser tests (3 passed)
• intrade_bar_api_response_test.exe --gtest_brief=1 (83 passed)
• header_only_odr_test.exe --gtest_brief=1 (4 passed)
• market_data_subscription_contract_test.exe --gtest_brief=1 (21 passed)