Cross-platform and documentation hardening patch.
- Adds native Windows user-local installation and centralized process, path, locking, UTF-8, and runtime activation portability boundaries.
- Adds installed-wheel deterministic acceptance across Linux x86_64, Windows x86_64, macOS Intel, and macOS arm64.
- Removes public per-page documentation edit actions while preserving the canonical GitHub source link, navigation, search, light/dark themes, and strict validation.
- Provides a new immutable Read the Docs snapshot so
stablecan advance beyond v0.5.1 without rewriting an existing tag.
Validated with 439 tests, strict MkDocs, release provenance checks, package builds, installed-wheel smoke, deterministic recovery/update/rollback acceptance, and the complete hosted platform matrix.