Webpage Integration: Update Legal Page Design & Scroll Behaviour

**Background/Context**
Privacy Policy & Terms of Use pages shipped as a Wagtail rich text page, integrated with the CMS and demoed May 15. New direction moves the page from a single rich text block to a structured, illustrated card-based layout.

**Scope**
- Rebuild front-end template for both pages to match the new illustrated, card-based design
- Convert content model from single rich text field to structured fields (StreamField or equivalent) supporting discrete cards + illustration slots
- Migrate existing content into the new structure — no data loss
- Preserve CMS integration behavior: `last_published_at` auto-population, editable via Wagtail admin
- Apply Boostlook.css tokens for new card/illustration components
- No-JS fallback for any new interactive elements

**Acceptance Criteria**

*Content model*
- [ ] Rich text field replaced with structured fields supporting individual cards and illustration slots
- [ ] Existing content migrated into new structure with no loss or corruption
- [ ] Editable in Wagtail admin without dev intervention post-launch

*Front-end*
- [ ] New template matches approved design (illustration + card sections)
- [ ] Fully responsive across breakpoints
- [ ] Scroll behaviour: For desktop and tablets, the top section (text + image) is anchored until the top section is viewed. See mock up [here](https://www.figma.com/design/5j0fQssrV9ipoU16P7hfKy/Website-Deliverables?node-id=10498-54427&t=plmKyBwTetzJ8Li8-4)
- [ ] Cards should flow into available space rather than enforce equal-height columns or match the Figma mockup pixel-perfectly.
- [ ] Renders correctly with JS disabled
- [ ] Uses Boostlook.css design tokens (no hardcoded values)

*CMS/Integration*
- [ ] `last_published_at` field continues to reflect correctly on edits
- [ ] No regressions to existing Wagtail routing/URL for the page

**Out of Scope**
- Copy changes to existing legal content

**Design Reference**
- New design: *https://www.figma.com/design/5j0fQssrV9ipoU16P7hfKy/Website-Deliverables?node-id=1995-46467