feat(offline): hoist sync UI to homepage, slow auto-sync to weekly

Move OfflineSyncIndicator (logo pip) and OfflineSyncBanner from the
[recipeLang] layout/page to (main)/+layout.svelte and (main)/+page.svelte.
Sync is an app-wide concern, not recipe-specific, and surfacing it on the
homepage gives the entry point users actually see when they install the
PWA. Indicator pulls language from languageStore since (main) doesn't
have data.lang from a recipe-scoped load.

Drop the now-unused .banner-wrap CSS and OfflineSyncIndicator/Banner
imports from the recipe routes.

Auto-sync cadence:
- AUTO_SYNC_INTERVAL 30 min -> 1 week. Recipes don't change often enough
  to justify a half-hourly background download (the user explicitly
  wanted this dialed back).
- Internal poll tick 5 min -> 1 hour. Polling 12x an hour for a weekly
  event is wasted work; hourly is fine and still responsive when the
  weekly window opens.

Bump 1.65.3 -> 1.66.0.

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "homepage",
-	"version": "1.65.3",
+	"version": "1.66.0",
 	"private": true,
 	"type": "module",
 	"scripts": {