fix: port 7 web features and repair the endless-loading screens

Root cause behind most "stuck loading" reports: the backend changed shape
(schedules became an array, location_preferences a string) while the mobile
parser still hard-cast to Map/int. The TypeError was swallowed by a silent
catch that returned null, and screens only handled the success state, so a
parse failure rendered as a permanent spinner. Same class of bug appeared
across service lists via non-null map lookups and a total absence of
request timeouts.

Ported from prosappweb:
- in-app suggestions (POST /suggestions)
- policies/terms from GET /settings/policies
- configurable appointment length (slot_duration_minutes)
- block/unblock calendar slots (POST /services/block)
- GPS city detection on the profile (Nominatim)
- server-side professional search with haversine distance
- retry cooldown after a rejected professional application

Reliability:
- parse schedules array (day_of_week 0=Mon) and string location_preferences
- read times as wall clock, so 08:00 stays 08:00 across timezones
- carry minutes into hours in TimeOfDay.add; a minute-based step used to
  loop forever and freeze the calendar (covered by test/time_slots_test.dart)
- semver update check instead of string equality, which blocked every build
  that did not exactly match the configured version
- request timeouts across all repositories
- surface HTTP >= 400 instead of reporting failed writes as success
- error states with retry instead of an indefinite shimmer

Includes pre-existing uncommitted work from the UI redesign.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

lib/screens/configuration/configuration_about_screen.dart

@@ -1,12 +1,10 @@
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:injector/injector.dart';
 import 'package:package_info_plus/package_info_plus.dart';
 import 'package:prosappco/components/general_drawer_item.dart';
-import 'package:prosappco/screens/web/web_view_screen.dart';
+import 'package:prosappco/screens/configuration/policy_text_screen.dart';
 import 'package:setting_repository/setting_repository.dart';
-import 'package:url_launcher/url_launcher.dart';
 import 'dart:io' show Platform;
 
 class ConfigurationAboutScreen extends StatefulWidget {
@@ -37,15 +35,24 @@ class _ConfigurationAboutScreenState extends State<ConfigurationAboutScreen> {
         );
   }
 
-  void _launchURL(String url) async {
-    if (await canLaunch(url)) {
-      await launch(url, forceSafariVC: false, forceWebView: false);
-    } else {
-      throw 'No se pudo abrir el enlace $url';
+  Future<void> _openPolicy(String title, String Function(PoliciesEntity) pick) async {
+    try {
+      final policies = await settingRepository.getPolicies();
+      if (!mounted) return;
+      Navigator.push(
+        context,
+        CupertinoPageRoute(
+          builder: (_) => PolicyTextScreen(title: title, content: pick(policies)),
+        ),
+      );
+    } catch (_) {
+      if (!mounted) return;
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(content: Text('No se pudo cargar el contenido')),
+      );
     }
   }
 
-
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -56,44 +63,18 @@ class _ConfigurationAboutScreenState extends State<ConfigurationAboutScreen> {
         children: [
           GeneralDrawerItem(
             label: 'Políticas de privacidad',
-            onTap: () {
-              if (kIsWeb) {
-                _launchURL(settings?.politicasPrivacidad ?? '');
-              } else {
-                Navigator.push(
-                  context,
-                  CupertinoPageRoute(
-                    builder: (BuildContext context) {
-                      return WebViewScreen(
-                        label: 'Políticas de privacidad',
-                        link: settings?.politicasPrivacidad ?? '',
-                      );
-                    },
-                  ),
-                );
-              }
-            },
+            onTap: () => _openPolicy(
+              'Políticas de privacidad',
+              (p) => p.privacy,
+            ),
             trailing: true,
           ),
           GeneralDrawerItem(
             label: 'Términos y condiciones',
-            onTap: () {
-              if (kIsWeb) {
-                _launchURL(settings?.terminosCondiciones ?? '');
-              } else {
-                Navigator.push(
-                  context,
-                  CupertinoPageRoute(
-                    builder: (BuildContext context) {
-                      return WebViewScreen(
-                        label: 'Términos y condiciones',
-                        link: settings?.terminosCondiciones ?? '',
-                      );
-                    },
-                  ),
-                );
-              }
-            },
+            onTap: () => _openPolicy(
+              'Términos y condiciones',
+              (p) => p.terms,
+            ),
             trailing: true,
           ),
           Platform.isIOS