replace: swap prosappweb content for prosapp_web_app (more complete version)

prosapp_web_app has chat, dashboard, calendar, support, 13 providers and
Fluro URL routing. Keep Dockerfile + nginx.conf from previous prosappweb.
Upgrade google_fonts 6.2.1 → 8.1.0 (Dart 3.12 compat fix).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/ui/views/blank_view.dart

@@ -0,0 +1,24 @@
+import 'package:prosapp_web_app/ui/cards/white_card.dart';
+import 'package:prosapp_web_app/ui/labels/custom_labels.dart';
+import 'package:flutter/material.dart';
+
+class BlankView extends StatelessWidget {
+  const BlankView({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      child: ListView(
+        physics: const ClampingScrollPhysics(),
+        children: [
+          Text('Blank view', style: CustomLabels.h1),
+          SizedBox(height: 10),
+          WhiteCard(
+            title: 'Blank',
+            child: Text('Blank View'),
+          ),
+        ],
+      ),
+    );
+  }
+}