## What
Restores the **Product** link to the site nav (removed in #21794),
reversing that commit's nav-structure change:
- **Menu** — Product is the first top-level item (in place of Why);
**Why** moves back into the **Resources** dropdown with its `why.webp`
preview (`IconBulb`, "Why teams choose Twenty").
- **Footer** — Product added to the **Sitemap** group (after Home).
The `/product` and `/why-twenty` routes already exist and are in the
sitemap; only the nav data changed. The rest of #21794 (dropdown frame
height, preview assets, current-page highlight) is untouched.
## Notes
- New `msg` strings (`Product`, and Why's restored strings) are left to
CI / the i18n bot to extract + translate — no catalog changes here.
## Testing
- `nx lint twenty-website` ✓ (check-conventions + oxlint + oxfmt)
- `nx typecheck twenty-website` ✓
Abdullah.
3474d75b56