Add LICENSE.txt (CC BY 4.0)

Adds the full CC BY 4.0 license for the white paper and associated assets.

Applies to:
- AI_Visibility_Retrieval_Dynamics_White_Paper_v1.0.pdf
- figures/ (charts/illustrations)
- data/ (example CSV)
- README.md, references.bib, CITATION.cff, CHANGELOG.md

Permissions:
- Share and adapt, including commercial use, with attribution.

Attribution requirement:
- Include title, authors, year, and DOI link.

Canonical DOI:
- https://doi.org/10.5281/zenodo.17117353

Preferred citation:
- Sheals, P., & de Rosen, T. (2025). AI Visibility Retrieval Dynamics (v1.0). The AIVO Standard. https://doi.org/10.5281/zenodo.17117353

Trademarks:
- AIVO Standard™ and PSOS™ are trademarks of The AIVO Standard.

Contact:
- hello@aivostandard.org

Full license text:
- https://creativecommons.org/licenses/by/4.0/

LICENSE.txt

@@ -0,0 +1,24 @@
+AI Visibility Retrieval Dynamics: Tiered Citation Platforms, Decay, and the Governance Gap in LLM Discoverability
+Copyright © 2025 Paul Sheals and Tim de Rosen, The AIVO Standard™
+
+This work is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
+
+You are free to:
+  • Share — copy and redistribute the material in any medium or format
+  • Adapt — remix, transform, and build upon the material for any purpose, even commercially
+
+Under the following terms:
+  • Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made.
+    Please include the title, authors, year, and the DOI link.
+  • No additional restrictions — You may not apply legal terms or technological measures that legally restrict others
+    from doing anything the license permits.
+
+Full legal code: https://creativecommons.org/licenses/by/4.0/
+
+Preferred citation:
+Sheals, P., & de Rosen, T. (2025). AI Visibility Retrieval Dynamics: Tiered Citation Platforms, Decay, and the Governance Gap in LLM Discoverability (v1.0). The AIVO Standard. https://doi.org/10.5281/zenodo.17117353
+
+Trademarks:
+AIVO Standard™ and PSOS™ (Prompt-Space Occupancy Score) are trademarks of The AIVO Standard. Third-party names are the property of their respective owners.
+
+Contact: paul@aivostandard.org