Next refactors

lib/data/services/embedding_service.dart

@@ -0,0 +1,30 @@
+import 'package:dio/dio.dart';
+import 'package:trainhub_flutter/core/constants/ai_constants.dart';
+
+/// Wraps the Nomic embedding server (llama.cpp).
+/// Returns a 768-dimensional float vector for any input text.
+class EmbeddingService {
+  final _dio = Dio(
+    BaseOptions(
+      connectTimeout: AiConstants.embeddingConnectTimeout,
+      receiveTimeout: AiConstants.embeddingReceiveTimeout,
+    ),
+  );
+
+  /// Returns the embedding vector for [text].
+  /// Throws a [DioException] if the Nomic server is unreachable.
+  Future<List<double>> embed(String text) async {
+    final response = await _dio.post<Map<String, dynamic>>(
+      AiConstants.embeddingApiUrl,
+      data: {
+        'input': text,
+        'model': AiConstants.nomicModelName,
+      },
+    );
+
+    final raw =
+        (response.data!['data'] as List<dynamic>)[0]['embedding']
+            as List<dynamic>;
+    return raw.map((e) => (e as num).toDouble()).toList();
+  }
+}