[FEATURE] License tracking and rights metadata for assets and published projects

[aernw]

Objective

Track rights and license metadata for assets and public-facing project content.

Scope

• rights metadata on assets, templates, or published project components
• backend rules for associating license information with reusable content
• groundwork for trust and moderation around public distribution

Out of Scope

• [Features explicitly not included]
• [Future enhancements to defer]

Acceptance Criteria

• rights information is structured and queryable instead of ad hoc text
• public asset and project distribution can be discussed with more confidence

Dependencies

Blocked by: (none)

Blocks: (none)

Success Metrics

• [How to measure success - optional]

Roadmap Context

Milestone: M7 - Launch Readiness & Cross-DAW Expansion
Parent workstream(s): #155, #214