feat(front): add app icon for android, web and windows + agenda stub

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/web/manifest.json

@@ -3,19 +3,19 @@
     "short_name": "P'titsPas",
     "start_url": ".",
     "display": "standalone",
-    "background_color": "#FFFEF9",
-    "theme_color": "#8AD0C8",
+    "background_color": "#ffffff",
+    "theme_color": "#ffffff",
     "description": "P'titsPas - Grandir pas à pas, sereinement",
     "orientation": "portrait-primary",
     "prefer_related_applications": false,
     "icons": [
         {
-            "src": "assets/images/icon.png",
+            "src": "icons/Icon-192.png",
             "sizes": "192x192",
             "type": "image/png"
         },
         {
-            "src": "assets/images/icon.png",
+            "src": "icons/Icon-512.png",
             "sizes": "512x512",
             "type": "image/png"
         },
@@ -32,4 +32,4 @@
             "purpose": "maskable"
         }
     ]
-}
+}