Clarify hosted walkthrough credit and media permissions

[3dhlab]

The hosted walkthrough includes an authorized presentation of participant and collection content. Its README and licensing notices should state the permission scope and credit Unlock Digital for the recording and editing, alongside the separately credited Lab demo code and authoring tutorial.

This draft proposes five documentation changes:

• Credit Unlock Digital next to the hosted README video link and retain the original captions/attribution.
• Record the maintainer's October 4 confirmation of permission to show participants in this video. The video and its previews, including the depicted interviews, models and research content, receive no reuse license and are explicitly excluded from the software's Apache 2.0 license in LICENSE_STATUS.md, NOTICE and media documentation.
• State that underlying collection datasets, source interviews and source 3D models remain outside the repository. The edited walkthrough is publicly viewable and downloadable.
• Use the still poster in the README so readers choose when motion and audio start; retain the animated GIF as an optional preview.

Base and integration path

This is a review patch for #6, based on upstream branch review/unlock-walkthrough-6, an exact review copy of Unlock Digital's current fork head 9eb9371d7efde47acf17330fb78498500a56f7b2. It preserves both original Unlock Digital commits; this PR's diff contains only the five maintainer documentation edits, with no media or runtime change.

Unlock Digital should assess and adopt the wording into its original fork PR, with appropriate credit retained. This draft is not intended to be merged to main or used as a release branch. After incorporation into #6, close this review draft and evaluate the updated #6 head through the protected review process. No contributor fork or existing #6 head has been edited by this draft.

Validation and hold

The complete 64.5-second H.264/AAC walkthrough decoded, sampled feature/participant/citation frames were inspected, and the GIF/poster metadata was checked. Only the edited video and derived previews are present; underlying collection files are absent. The combined Lab-plus-hosted review snapshot is conflict-free and passes the fixture boundary, selected credential-pattern and relative-link checks.

The documentation draft passed API, browser and clean-demo CI. Its web check fails only on the mirrored base's inherited brace-expansion dependency audit; the patches in #7 address those dependency pins and all four checks now pass on #7. Its fresh CI must be assessed after integration with the reviewed Lab changes. Green checks would not establish a reuse license for research content.

The owner will assess the PRs together on the next review day. No main merge, tag or release is authorized by this draft.