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/components/general_drawer_item.dart

@@ -20,28 +20,23 @@ class GeneralDrawerItem extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final onSurface = Theme.of(context).colorScheme.onSurface;
     return ListTile(
       onTap: onTap == null ? null : () => onTap!(),
       leading: leading == null
           ? null
-          : Icon(
-              leading,
-              color: Colors.black,
-            ),
+          : Icon(leading, color: color ?? onSurface.withOpacity(0.75)),
       trailing: trailing
-          ? const Icon(
-              Icons.keyboard_arrow_right,
-              color: Colors.black,
-            )
+          ? Icon(Icons.keyboard_arrow_right, color: onSurface.withOpacity(0.4))
           : null,
       title: Text(
         label,
-        style: TextStyle(fontSize: 15, color: color),
+        style: TextStyle(fontSize: 15, color: color ?? onSurface),
       ),
       subtitle: subtitle == null
           ? null
-          : Text(subtitle ?? "", style: const TextStyle(color: Colors.black54)),
-      // dense: true,
+          : Text(subtitle!,
+              style: TextStyle(color: onSurface.withOpacity(0.55))),
     );
   }
 }