Valence Shell v1.0.0 - Production Ready for Compliance Environments

Production-ready release with GDPR compliance and enhanced UX.

Highlights:
- GDPR Article 17 & 30 compliance (secure deletion + audit logging)
- fish/zsh-level UX (syntax highlighting, command correction, smart pager)
- 187 tests passing (unit + integration + property-based)
- ClusterFuzzLite fuzzing integration
- OpenSSF Scorecard compliant
- 10ms startup time, 3.2MB binary
- Comprehensive documentation (USER_GUIDE, CONTRIBUTOR_GUIDE, PROOF_OVERVIEW)

See CHANGELOG.md for full details.

chore: fix license headers to PMPL-1.0-or-later

- Update SPDX identifiers from AGPL to PMPL
- Ensure LICENSE file uses PMPL-1.0-or-later
- Maintain consistency with palimpsest-license repo

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>