docs+tooling: doc-freshness gate, documentation-pass policy, token-hygiene

Refresh CLAUDE.md for v0.10.0 (3 CI jobs incl. disabled test-cgal,
compile-time option matrix, reviewer/pages docs, agentic + token-hygiene
workflow patterns) and condense the historical Phase-8/audit logs to
pointers.

Add the documentation-pass process so the single-source-of-truth rules
stay enforced:
  * scripts/quality/check-doc-freshness.sh — string-only drift gate
    (version/date across CITATION/CHANGELOG/CLAUDE, doc-map count), <1 s,
    registered in run-all.sh + quality README.
  * doc/release-policy.md — "Documentation passes" subsection (triggers +
    docs:sync rule); fix stale Phase-milestone mapping (v0.10.0 was
    reviewer-ready, 9c→v0.11.0) and the test-cgal CI mention.

Add shared Claude config (un-ignore the two files only):
  * .claude/settings.json — permission allowlist for safe repo commands.
  * .claude/token-hygiene.md — Tier-3 cache-discipline user guide that
    CLAUDE.md instructs Claude to remind the user about.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/quality/README.md

@@ -19,6 +19,7 @@ consistency + markdown links + end-to-end smoke via `try_it.sh`).
 | Script | What it checks | Wall time | Prereqs |
 |---|---|---|---|
 | `license-headers.sh` | every C++ source carries `SPDX-License-Identifier: MIT` | ~1 s | `bash` |
+| `check-doc-freshness.sh` | string-only doc drift: version/date agree across CITATION/CHANGELOG/CLAUDE; doc-map count matches `doc/**/*.md` | <1 s | `bash` |
 | `cgal-conventions.py` | CGAL-1…6: include-guard format, `\file` brief, namespace nesting, tag-naming, no `using namespace`, no stray `#define` | ~1 s | `python3` |
 | `clang-format.sh` | every C++ source matches `.clang-format` (dry-run by default; `--fix` to apply) | ~2 s | `clang-format` ≥ 15 |
 | `cmake-format.sh` | every `CMakeLists.txt` matches `.cmake-format.yaml` + passes `cmake-lint` | ~2 s | `cmake-format` (pip: cmakelang) |