refactor: rename nutriphi module to food (Essen)

Complete rename across the entire monorepo pre-launch:
- Module, routes, API, i18n, standalone landing app directories
- All code identifiers, display names, logo component
- German user-facing label: "Essen" (English brand stays "Food")
- Dexie table nutriFavorites -> foodFavorites
- Infra configs (docker-compose, cloudflared, nginx, wrangler)

Zero residue of nutriphi remains. No data migration needed (pre-launch).

Follow-up: run pnpm install, update Cloudflare DNS
(food.mana.how), rename Cloudflare Pages project.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/dependabot.yml

@@ -98,7 +98,7 @@ updates:
       - "automated"
 
   - package-ecosystem: "docker"
-    directory: "/apps/nutriphi/apps/backend"
+    directory: "/apps/food/apps/backend"
     schedule:
       interval: "weekly"
     open-pull-requests-limit: 5