feat: server-side search with debounce for professionals list

- getProfessionals() now accepts optional search param sent to ?search=
- updateCity only triggers the initial load (city no longer used as filter)
- Search field debounces 450ms before firing API call
- TextEditingController added so clear button also resets the field
- Client-side filtering removed (API now handles it and returns top 7)

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

lib/ui/views/professionals_view.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:prosapp_web_app/models/usuario_profesional.dart';
 import 'package:prosapp_web_app/providers/professionals_provider.dart';
@@ -14,19 +15,35 @@ class ProfessionalsView extends StatefulWidget {
 
 class _ProfessionalsViewState extends State<ProfessionalsView> {
   String _search = '';
+  Timer? _debounce;
+  final _controller = TextEditingController();
+
+  @override
+  void dispose() {
+    _debounce?.cancel();
+    _controller.dispose();
+    super.dispose();
+  }
+
+  void _onSearchChanged(String value) {
+    setState(() => _search = value);
+    _debounce?.cancel();
+    _debounce = Timer(const Duration(milliseconds: 450), () {
+      context.read<ProfessionalsProvider>().getProfessionals(search: value);
+    });
+  }
+
+  void _clearSearch() {
+    _controller.clear();
+    _onSearchChanged('');
+  }
 
   @override
   Widget build(BuildContext context) {
     final provider = context.watch<ProfessionalsProvider>();
     final isDark = context.watch<ThemeProvider>().isDark;
 
-    final filtered = provider.professionals.where((p) {
-      if (_search.isEmpty) return true;
-      final q = _search.toLowerCase();
-      return p.user.name.toLowerCase().contains(q) ||
-          p.professionalInfo.profession.toLowerCase().contains(q) ||
-          (p.user.city ?? '').toLowerCase().contains(q);
-    }).toList();
+    final filtered = provider.professionals;
 
     final cardBg = isDark ? const Color(0xFF1E293B) : Colors.white;
     final border = isDark ? const Color(0xFF334155) : const Color(0xFFE5E7EB);
@@ -39,7 +56,8 @@ class _ProfessionalsViewState extends State<ProfessionalsView> {
         Padding(
           padding: const EdgeInsets.fromLTRB(0, 0, 0, 14),
           child: TextField(
-            onChanged: (v) => setState(() => _search = v),
+            controller: _controller,
+            onChanged: _onSearchChanged,
             style: TextStyle(
               color: isDark ? Colors.white : const Color(0xFF111827),
               fontSize: 14,
@@ -52,7 +70,7 @@ class _ProfessionalsViewState extends State<ProfessionalsView> {
               suffixIcon: _search.isNotEmpty
                   ? IconButton(
                       icon: Icon(Icons.close, size: 18, color: hintColor),
-                      onPressed: () => setState(() => _search = ''),
+                      onPressed: _clearSearch,
                     )
                   : null,
               filled: true,