Establish top-level repository licensing and attribution

### Description

Confirm and publish the approved licensing and attribution terms for the public repository so contributors and downstream users have unambiguous reuse and contribution guidance.

### Action Items

- [ ] Confirm the approved Hack for LA organization license and any legal, fiscal-sponsorship, or organizational requirements before selecting repository terms.
- [ ] Audit the repository for existing licenses, notices, third-party code/assets, generated artifacts, and license references, including `data-science/LICENSE`.
- [ ] Decide whether the data-science license should match the repository-wide license or remain distinct; document the rationale.
- [ ] Add the approved top-level `LICENSE` file and any required `NOTICE`, attribution, or third-party-license documentation.
- [ ] Update repository documentation and package metadata where appropriate to reference the canonical license.
- [ ] Verify that the license is detected correctly by GitHub and that references do not conflict.
- [ ] Have an authorized project/organization maintainer review the final terms before merge.

### Additional Information

Priority: low. This is governance/documentation work and should not delay active compliance, testing, security-scanning, or contributor-documentation work.

Do not copy a license from another project or make legal assumptions without confirming the organization-approved terms.

Start by confirming the Hack for LA organization-approved terms with an authorized maintainer, then audit the repository for existing licenses, notices, third-party assets, generated artifacts, and references, including data-science/LICENSE. Document whether that license remains distinct, add the approved top-level LICENSE and any required notices, update relevant documentation and metadata, and verify GitHub detection and consistency.

Written by the indexing model from the issue text.