feat: redesign sidebar with corporate branding and ProsApp logo

- Logo: network image in white card + tagline
- Sidebar: deep navy gradient (#0D1B3E) with blue accent active states
- MenuItem: left accent bar indicator, cleaner hover, better contrast
- Mode toggle: gradient button matching brand colors
- TextSeparator: uppercase label with divider line

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

lib/ui/shared/widgets/text_separator.dart

@@ -1,20 +1,29 @@
 import 'package:flutter/material.dart';
-import 'package:google_fonts/google_fonts.dart';
 
 class TextSeparator extends StatelessWidget {
   final String text;
-
   const TextSeparator({super.key, required this.text});
 
   @override
   Widget build(BuildContext context) {
-    return Container(
-      padding: EdgeInsets.symmetric(horizontal: 20),
-      margin: EdgeInsets.only(bottom: 5),
-      child: Text(
-        text,
-        style: GoogleFonts.roboto(
-            color: Colors.white.withOpacity(0.3), fontSize: 12),
+    return Padding(
+      padding: const EdgeInsets.fromLTRB(20, 16, 20, 4),
+      child: Row(
+        children: [
+          Text(
+            text.toUpperCase(),
+            style: const TextStyle(
+              color: Color(0xFF4A6F8A),
+              fontSize: 10,
+              fontWeight: FontWeight.w600,
+              letterSpacing: 1.2,
+            ),
+          ),
+          const SizedBox(width: 8),
+          const Expanded(
+            child: Divider(color: Color(0xFF1E3A52), thickness: 1, height: 1),
+          ),
+        ],
       ),
     );
   }