Features:
- Add field-level learning to TOIN from retrieved items
- CompressionStore now passes retrieved_items to TOIN for learning
- Add FieldSemantics class for tracking field usage patterns
Test improvements:
- Add TestCacheOptimizerInvocation to verify optimizer is actually invoked
- Add TestSemanticCacheIntegration to verify cache hit returns without API call
- Add TestSessionStatsTracking to verify session stats are tracked
- Add TestEndToEndTOINIntegration for full CCR cycle with TOIN
- Add critical field_semantics assertions to catch feedback loop bugs
Fixes:
- Remove unused imports and variables (ruff linting)
Bump version to 0.2.11
