Add error handling and update documentation

DEVELOPER.md

@@ -488,8 +488,7 @@ The major performance issue was discovered to be double caching with expensive o
 
 **Current state:**
 - **Search functionality**: Fully implemented and active
-- **Basic routing**: Complete but disabled pending API integration
-- **Avoidance routing**: Awaiting alprwatch.org/directions API
+- **Avoidance routing**: Fully implemented and active
 - **Offline routing**: Requires vector map tiles
 
 **Architecture:**
@@ -848,4 +847,4 @@ debugPrint('[ComponentName] Detailed message: $data');
 
 ---
 
-This documentation should be updated as the architecture evolves. When making significant changes, update both the relevant section here and add a brief note explaining the rationale for the change.
+This documentation should be updated as the architecture evolves. When making significant changes, update both the relevant section here and add a brief note explaining the rationale for the change.

lib/dev_config.dart

@@ -77,6 +77,7 @@ const bool kEnableNodeExtraction = false; // Set to true to enable extract from
 
 /// Navigation availability: only dev builds, and only when online
 bool enableNavigationFeatures({required bool offlineMode}) {
+  return true;
   if (!kEnableDevelopmentModes) {
     return false; // Release builds: never allow navigation
   } else {

lib/services/routing_service.dart

@@ -84,9 +84,8 @@ class RoutingService {
       // Check alprwatch response status
       final ok = data['ok'] as bool? ?? false;
       if ( ! ok ) {
-        final code = data['error']['code'] as String? ?? 'Unknown routing error code';
-        final message = data['error']['message'] as String? ?? 'Unknown routing error';
-        throw RoutingException('alprwatch error ($code): $message');
+        final message = data['error'] as String? ?? 'Unknown routing error';
+        throw RoutingException('alprwatch error: $message');
       }
       
       final route = data['result']['route'] as Map<String, dynamic>?;