fix(pwa): cache-bust icon link tags (?v=20260515-3a)

iOS Safari caches the apple-touch-icon per origin and ignores byte-level
changes on the same URL. Adding a version query forces a refetch on
fresh visits without renaming the source files. Buttressed across all
standalone Twig templates and the SPA index plus the manifest icons so
Chrome desktop also refetches.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/public/manifest.webmanifest

@@ -11,19 +11,19 @@
   "theme_color": "#fdf6ee",
   "icons": [
     {
-      "src": "/build/icons/icon-192.png",
+      "src": "/build/icons/icon-192.png?v=20260515-3a",
       "sizes": "192x192",
       "type": "image/png",
       "purpose": "any"
     },
     {
-      "src": "/build/icons/icon-512.png",
+      "src": "/build/icons/icon-512.png?v=20260515-3a",
       "sizes": "512x512",
       "type": "image/png",
       "purpose": "any"
     },
     {
-      "src": "/build/icons/icon-512-maskable.png",
+      "src": "/build/icons/icon-512-maskable.png?v=20260515-3a",
       "sizes": "512x512",
       "type": "image/png",
       "purpose": "maskable"