Migrate current DigSubAnalyzer line to GPL with commercial licensing

[masarray]

Licensing model

• preserves the final active Apache-2.0 revision at 85d43a0fe58a5888a9e8008c168ab76d2333ea87 on archive/apache-2.0-final
• licenses revisions after that boundary and post-transition release packages under GPL-3.0-or-later only
• advances the post-transition package version to 1.4.0-beta.2 so it is not confused with historical Apache-licensed v1.4.0-beta.1 artifacts
• adds a separate negotiated commercial path for proprietary integration, OEM or white-label distribution, closed-source redistribution, private branches, support, training, warranty, and engineering services
• states that the commercial notice is not itself a license and grants no additional rights

Governance and provenance

• adds copyright, trademark, Contributor License Agreement, and Developer Certificate of Origin records
• records the license transition, external-IP/provenance boundary, and public wording/claim boundary
• requires contributor authority, DCO sign-off, provenance disclosure, and synthetic or authorized sanitized fixtures

Public presentation

• updates README, landing-page structured data, visible licensing section, FAQ, manifest, changelog, contribution guidance, and support wording
• keeps configured expectations, observed traffic, software interpretation, and external-device behavior separate
• avoids unqualified conformance, calibration, deterministic timing, functional-safety, cybersecurity, switching-authority, universal-interoperability, and IED-acceptance claims

Packaging and validation

• includes GPL, NOTICE, commercial, copyright, trademark, third-party, and licensing-summary documents in post-transition portable packages
• rejects stale Apache licensing presented as current package licensing
• adds licensing and package-content checks to the repository-health gate
• runs candidate packaging for legal/* branches
• records the current community license and historical boundary in candidate and release manifests

Legal scope

This repository record supports the intended public licensing transition but does not by itself resolve employment, invention-assignment, confidentiality, customer, educational, sponsorship, trademark, or private-artifact obligations. A significant commercial agreement should review the exact rights and deliverables involved.