PandaMart Complete InfinityFree Edition v4.0

Release goals:
- Preserve the existing PandaMart storefront/admin functionality.
- Fix broken fresh-install SQL (including duplicate coupon column).
- Add a safe, idempotent admin upgrade path for existing databases.
- Enforce genuine purchase-linked reviews.
- Add secure customer profile/photo and customer messaging.
- Add order fraud-risk scoring and manual verification state.
- Add editable homepage banners (maximum 4 total).
- Add editable Partners in the footer with safe external links.
- Add basic marketing campaign management and UTM attribution.
- Add product SEO title/description, canonical/OG metadata and dynamic sitemap.
- Remain suitable for InfinityFree/shared hosting: PHP + MySQL + normal Apache features only.
