Fix ruff formatting

Add TOIN field-level learning and comprehensive integration tests

Add CCR marker support to all compressors and fix retrieval

Add opt-in text compression utilities for coding tasks

Add deterministic anchor matching to all compression plans

Fix all mypy type errors and flaky embedding test

Fix all ruff lint and format errors for CI

feat: Add CCR architecture, TOIN telemetry, and DevEx improvements

Prepare for OSS release v0.2.0

Initial commit: Headroom SDK - LLM context optimization toolkit