Close patch 0.1.2 Python install wording

[docushell-dev]

Summary

• update public README, Python package docs, and public claim inventory to install ethos-pdf==0.1.2
• add a Python public install wording closeout record and guard
• convert earlier install-wording guards to validate their historical records instead of preserving stale current 0.1.1 Python wording
• keep package tag creation, hosted, production, Windows, bundled PDFium, benchmark, ethos-doc, and ethos-rag surfaces blocked

Verification

• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_2_python_public_install_wording_closeout.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_public_prealpha_wording_approval.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_execution_status.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_2_rust_public_install_wording_closeout.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_2_public_install_wording_closeout.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_2_version_activation.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_2_crates_publication_approval_request.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_2_crates_publication_closeout.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_milestone_e_public_beta_source_only_approval.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_milestone_e_public_evaluation_current_state_closeout.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_patch_0_1_1_public_install_wording_closeout.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/test_release_candidate_prep.py
• PYTHONDONTWRITEBYTECODE=1 python3 .github/scripts/public_boundary_claims_gate.py
• git diff --check
• make light-check PYTHON=python3
• make milestone-e-prep PYTHON=python3
• make release-candidate-prep PYTHON=python3