feat(cache): Add lightweight in-memory cache with TTL and LRU eviction

lib/core/models/backend_config.dart

@@ -35,16 +35,27 @@ class BackendConfig {
   }
 
   Map<String, dynamic> toJson() {
-    return <String, dynamic>{'enable_websocket': enableWebsocket};
+    return <String, dynamic>{
+      'enable_websocket': enableWebsocket,
+    };
   }
 
   static BackendConfig fromJson(Map<String, dynamic> json) {
     bool? enableWebsocket;
-    final features = json['features'];
-    if (features is Map<String, dynamic>) {
-      final value = features['enable_websocket'];
-      if (value is bool) {
-        enableWebsocket = value;
+    // Try canonical format first
+    final value = json['enable_websocket'];
+    if (value is bool) {
+      enableWebsocket = value;
+    }
+
+    // Fallback to nested format for backwards compatibility
+    if (enableWebsocket == null) {
+      final features = json['features'];
+      if (features is Map<String, dynamic>) {
+        final nestedValue = features['enable_websocket'];
+        if (nestedValue is bool) {
+          enableWebsocket = nestedValue;
+        }
       }
     }
 

lib/core/models/model.dart

@@ -20,6 +20,18 @@ sealed class Model with _$Model {
   }) = _Model;
 
   factory Model.fromJson(Map<String, dynamic> json) {
+    final cachedIsMultimodal = switch (json['isMultimodal']) {
+      final bool value => value,
+      _ => json['is_multimodal'] is bool ? json['is_multimodal'] as bool : null,
+    };
+    final cachedSupportsStreaming = switch (json['supportsStreaming']) {
+      final bool value => value,
+      _ =>
+        json['supports_streaming'] is bool
+            ? json['supports_streaming'] as bool
+            : null,
+    };
+
     // Handle different response formats from OpenWebUI
 
     // Extract architecture info for capabilities
@@ -29,8 +41,9 @@ sealed class Model with _$Model {
 
     // Determine if multimodal based on architecture
     final isMultimodal =
-        modality?.contains('image') == true ||
-        inputModalities?.contains('image') == true;
+        cachedIsMultimodal ??
+        (modality?.contains('image') == true ||
+            inputModalities?.contains('image') == true);
 
     // Extract supported parameters robustly (top-level or nested under provider keys)
     List? supportedParams =
@@ -63,7 +76,8 @@ sealed class Model with _$Model {
     }
 
     // Determine streaming support from supported parameters if known
-    final supportsStreaming = supportedParams?.contains('stream') ?? true;
+    final supportsStreaming =
+        cachedSupportsStreaming ?? supportedParams?.contains('stream') ?? true;
 
     // Convert supported parameters to List<String> if present
     final supportedParamsList = supportedParams
@@ -154,4 +168,22 @@ sealed class Model with _$Model {
       toolIds: toolIds,
     );
   }
+
+  Map<String, dynamic> toJson() {
+    final data = <String, dynamic>{
+      'id': id,
+      'name': name,
+      'description': description,
+      'isMultimodal': isMultimodal,
+      'supportsStreaming': supportsStreaming,
+      'supportsRAG': supportsRAG,
+      'supported_parameters': supportedParameters,
+      'capabilities': capabilities,
+      'metadata': metadata,
+      'architecture': capabilities?['architecture'],
+      'toolIds': toolIds,
+    };
+    data.removeWhere((_, value) => value == null);
+    return data;
+  }
 }

lib/core/models/socket_transport_availability.dart

@@ -0,0 +1,23 @@
+class SocketTransportAvailability {
+  const SocketTransportAvailability({
+    required this.allowPolling,
+    required this.allowWebsocketOnly,
+  });
+
+  final bool allowPolling;
+  final bool allowWebsocketOnly;
+
+  Map<String, dynamic> toJson() {
+    return {
+      'allowPolling': allowPolling,
+      'allowWebsocketOnly': allowWebsocketOnly,
+    };
+  }
+
+  factory SocketTransportAvailability.fromJson(Map<String, dynamic> json) {
+    return SocketTransportAvailability(
+      allowPolling: json['allowPolling'] == true,
+      allowWebsocketOnly: json['allowWebsocketOnly'] == true,
+    );
+  }
+}

lib/core/models/tool.dart

@@ -23,4 +23,14 @@ sealed class Tool with _$Tool {
       meta: json['meta'] as Map<String, dynamic>?,
     );
   }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'name': name,
+      'description': description,
+      'user_id': userId,
+      'meta': meta,
+    };
+  }
 }

lib/core/models/user.dart

@@ -30,4 +30,16 @@ sealed class User with _$User {
       isActive: json['is_active'] as bool? ?? json['isActive'] as bool? ?? true,
     );
   }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'username': username,
+      'email': email,
+      'name': name,
+      'profile_image_url': profileImage,
+      'role': role,
+      'is_active': isActive,
+    };
+  }
 }