chore: prepare Python 0.8.0 release

[rlippmann]

What changed

• bump the Python package version to 0.8.0
• refresh package metadata keywords for the current authority-layer positioning
• refresh the published current demo verification matrix to the 2026-06 8-demo reruns while keeping the 0.6.15 matrix clearly historical
• tighten README, demos/README.md, and demo-results docs so current results, historical evidence, and the current demo set are described consistently
• harden the Demo 02 oracle so acceptable replacement phrasing like "instead of peanuts" is not misclassified as a prohibited-item violation
• package examples/, demos/, and host_support/ for installable examples/demos paths, while keeping litellm out of core dependencies
• document thread safety as a future consideration rather than a 0.8.x release item

Why

This prepares the Python 0.8.0 release with aligned versioning, release-facing docs, corrected current demo evidence, safer Demo 02 scoring, and packaging support that makes the documented examples/demos install paths true.

Checklist

• pre-commit run (uv run pre-commit run --all-files)
• tests pass (uv run pytest)
• package build (uv build)
• wheel inspection (python3 -m zipfile -l dist/context_compiler-0.7.10-py3-none-any.whl)
• sdist inspection (tar -tzf dist/context_compiler-0.7.10.tar.gz)
• clean core install/import check (python3 -m venv /tmp/cc_pkg_core && /tmp/cc_pkg_core/bin/pip install dist/context_compiler-0.7.10-py3-none-any.whl && /tmp/cc_pkg_core/bin/python -c "import context_compiler, importlib.util; print(context_compiler.__file__); print(importlib.util.find_spec('litellm'))")
• clean demos install/run check (python3 -m venv /tmp/cc_pkg_demos_net && /tmp/cc_pkg_demos_net/bin/pip install "context_compiler[demos] @ file:///Users/rlippmann/Source/context-compiler/dist/context_compiler-0.7.10-py3-none-any.whl" && PROVIDER=ollama MODEL=ollama/llama3.1:8b /tmp/cc_pkg_demos_net/bin/python -m demos.run_demo 6)
• clean examples install/run check (python3 -m venv /tmp/cc_pkg_examples && /tmp/cc_pkg_examples/bin/pip install "context_compiler[examples] @ file:///Users/rlippmann/Source/context-compiler/dist/context_compiler-0.7.10-py3-none-any.whl" && /tmp/cc_pkg_examples/bin/python /tmp/cc_pkg_examples/lib/python3.14/site-packages/examples/01_persistent_guardrails.py)