feat(offline): redesign sync UI and PWA polish

Split the single OfflineSyncButton into two surfaces with distinct
intents:
  - OfflineSyncBanner: dismissable promo on the recipe index that
    encourages first-time download (only when standalone + not yet
    synced).
  - OfflineSyncIndicator: small status pip overlaid on the nav logo
    when offline data is available, opening a popover with sync /
    clear actions.

Also fold the sync / clear actions into the UserHeader options menu so
the avatar dropdown is the canonical place to manage offline data.
Header.svelte gains a `logo_overlay` snippet slot to host the
indicator pip.

Other:
  - manifest.json: prefer the theme-aware SVG as the primary install
    icon and drop the redundant 512px raster (kept maskable 192px).
  - scripts/deploy.sh: build locally and rsync artifacts to the
    server, avoiding any pnpm/git work on the production host.

Bump 1.57.8 -> 1.58.0.

static/manifest.json

@@ -9,14 +9,14 @@
   "background_color": "#2E3440",
   "icons": [
     {
-      "src": "/favicon-192.png",
-      "sizes": "192x192",
-      "type": "image/png",
-      "purpose": "any maskable"
+      "src": "/favicon.svg",
+      "sizes": "any",
+      "type": "image/svg+xml",
+      "purpose": "any"
     },
     {
-      "src": "/favicon-512.png",
-      "sizes": "512x512",
+      "src": "/favicon-192.png",
+      "sizes": "192x192",
       "type": "image/png",
       "purpose": "any maskable"
     }