Close patch 0.1.1 public install wording

[docushell-dev]

Summary

• Document bounded patch 0.1.1 public install paths for published evaluation surfaces.
• Add PyPI install wording for ethos-pdf==0.1.1 while explicitly stating the Python wheel is a thin wrapper around a caller-provided local ethos CLI binary and does not bundle the CLI or PDFium.
• Guard the exact README/Python install wording through public-boundary claims and release-candidate-prep.

Boundary

• This PR documents already-published evaluation install paths only.
• Hosted surfaces, production positioning, Windows packaged artifacts, bundled project-maintained PDFium, public benchmark reports or claims, speed/footprint/parser-quality/table-quality claims, ethos-doc, and ethos-rag remain blocked.

Tests

• python3 .github/scripts/test_patch_0_1_1_public_install_wording_closeout.py
• python3 .github/scripts/public_boundary_claims_gate.py
• python3 .github/scripts/claims_gate.py
• python3 .github/scripts/test_public_surface_posture.py
• python3 .github/scripts/test_release_candidate_prep.py
• python3 .github/scripts/test_milestone_e_source_snapshot_candidate_audit.py
• python3 .github/scripts/test_python_public_api_policy.py
• PYTHONPATH=python python3 -m unittest discover -s python/tests
• make light-check PYTHON=python3
• make release-candidate-prep PYTHON=python3
• git diff --check
• git diff --cached --check