Advance learned-provider placement and runtime 0.2

[epi13]

Summary

• add backend-neutral CPU/full-CUDA/sequential CPU offload policy with reserve, cap, workspace, dtype probes, and bounded AUTO recovery
• add process-local Rust host lifecycle, reusable snapshots, bounded diagnostic normalization, measurements, quarantine, and executable HMM baseline
• add optional Torch evidence adapter and bounded investigator context/workspace contracts
• update schemas, roadmap, runtime architecture, threat model, and tests

Verification

• Python: 38 tests, compileall, Ruff
• Rust: fmt, Clippy -D warnings, 20 unit tests/doc-tests
• demo ledger verification and provider benchmark
• Joern baseline/post Rust query completed; parser produced empty method/call overlays, and Python frontend is unavailable in installed Joern