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/menu_item.dart

@@ -1,5 +1,10 @@
 import 'package:flutter/material.dart';
-import 'package:google_fonts/google_fonts.dart';
+
+const _kAccent = Color(0xFF42A4EF);
+const _kTextActive = Colors.white;
+const _kTextInactive = Color(0xFF8BAFD4);
+const _kIconActive = _kAccent;
+const _kIconInactive = Color(0xFF5A7A9B);
 
 class MenuItem extends StatefulWidget {
   final String text;
@@ -24,45 +29,54 @@ class _MenuItemState extends State<MenuItem> {
 
   @override
   Widget build(BuildContext context) {
-    return AnimatedContainer(
-      duration: const Duration(milliseconds: 300),
-      color: isHovered
-          ? Colors.white.withOpacity(0.1)
-          : widget.isActive
-              ? Colors.white.withOpacity(0.1)
-              : Colors.transparent,
-      child: Material(
-        color: Colors.transparent,
-        child: InkWell(
-          onTap: widget.isActive ? null : () => widget.onPressed(),
-          child: Padding(
-            padding: const EdgeInsets.symmetric(
-              horizontal: 30,
-              vertical: 10,
-            ),
-            child: MouseRegion(
-              cursor: widget.isActive
-                  ? SystemMouseCursors.basic
-                  : SystemMouseCursors.click,
-              onEnter: (_) => setState(() => isHovered = true),
-              onExit: (_) => setState(() => isHovered = false),
-              child: Row(
-                crossAxisAlignment: CrossAxisAlignment.center,
-                children: [
-                  Icon(
-                    widget.icon,
-                    color: Colors.white.withOpacity(0.3),
+    final active = widget.isActive;
+    final highlight = active || isHovered;
+
+    return MouseRegion(
+      cursor: active ? SystemMouseCursors.basic : SystemMouseCursors.click,
+      onEnter: (_) => setState(() => isHovered = true),
+      onExit: (_) => setState(() => isHovered = false),
+      child: GestureDetector(
+        onTap: active ? null : () => widget.onPressed(),
+        child: AnimatedContainer(
+          duration: const Duration(milliseconds: 200),
+          margin: const EdgeInsets.symmetric(horizontal: 12, vertical: 2),
+          decoration: BoxDecoration(
+            color: highlight
+                ? const Color(0xFF42A4EF).withOpacity(0.12)
+                : Colors.transparent,
+            borderRadius: BorderRadius.circular(10),
+          ),
+          child: Row(
+            children: [
+              AnimatedContainer(
+                duration: const Duration(milliseconds: 200),
+                width: 3,
+                height: 36,
+                decoration: BoxDecoration(
+                  color: active ? _kAccent : Colors.transparent,
+                  borderRadius: const BorderRadius.only(
+                    topRight: Radius.circular(3),
+                    bottomRight: Radius.circular(3),
                   ),
-                  const SizedBox(width: 10),
-                  Text(
-                    widget.text,
-                    style: GoogleFonts.roboto(
-                      color: Colors.white.withOpacity(0.8),
-                    ),
-                  ),
-                ],
+                ),
               ),
-            ),
+              const SizedBox(width: 12),
+              Icon(
+                widget.icon,
+                color: active ? _kIconActive : _kIconInactive,
+                size: 20,
+              ),
+              const SizedBox(width: 10),
+              Text(
+                widget.text,
+                style: TextStyle(
+                  color: active ? _kTextActive : _kTextInactive,
+                  fontSize: 13,
+                  fontWeight: active ? FontWeight.w600 : FontWeight.w400,
+                ),
+              ),
+            ],
           ),
         ),
       ),