mustache 3.0.0 — security major

The protections v2.1 introduced in report mode become the enforced
default, and every fail-open path found while hardening them is closed.
Null validator means the DEFAULT POLICY (spec 11.2); containers are
blocked by default with two escapes; getResolvedValues() types change;
Stringable is no longer trusted by shape; parse-time ceilings apply in
enforce, compound expressions included.

Read UPGRADE-3.md (ships in this dist) before updating. 2.x is
maintained for new vulnerabilities and Laravel compatibility until
2027-02-03.

Approved 2026-08-03 (approvals/majors/mustache-3.md, central workspace)
on candidate 1aca3db; tagged commit is docs-stamping only on top, code
tree identical.