Przebudowanie aplikacji, usprawnione AI, dodanie combo buildera

lib/data/repositories/note_repository_impl.dart

@@ -2,6 +2,7 @@ import 'dart:convert';
 import 'dart:math' show sqrt;
 
 import 'package:drift/drift.dart';
+import 'package:trainhub_flutter/core/constants/ai_constants.dart';
 import 'package:trainhub_flutter/data/database/app_database.dart';
 import 'package:trainhub_flutter/data/database/daos/knowledge_chunk_dao.dart';
 import 'package:trainhub_flutter/domain/repositories/note_repository.dart';
@@ -29,7 +30,11 @@ class NoteRepositoryImpl implements NoteRepository {
     final now = DateTime.now().toIso8601String();
 
     for (final chunk in chunks) {
-      final embedding = await _embeddingService.embed(chunk);
+      // Nomic v1.5 is trained with task prefixes — embedding without them
+      // noticeably degrades retrieval quality.
+      final embedding = await _embeddingService.embed(
+        '${AiConstants.nomicDocumentPrefix}$chunk',
+      );
       await _dao.insertChunk(
         KnowledgeChunksCompanion(
           id: Value(_uuid.v4()),
@@ -47,19 +52,19 @@ class NoteRepositoryImpl implements NoteRepository {
     final allRows = await _dao.getAllChunks();
     if (allRows.isEmpty) return [];
 
-    final queryEmbedding = await _embeddingService.embed(query);
+    final queryEmbedding = await _embeddingService.embed(
+      '${AiConstants.nomicQueryPrefix}$query',
+    );
 
     final scored = allRows.map((row) {
-      final emb =
-          (jsonDecode(row.embedding) as List<dynamic>)
-              .map((e) => (e as num).toDouble())
-              .toList();
+      final emb = (jsonDecode(row.embedding) as List<dynamic>)
+          .map((e) => (e as num).toDouble())
+          .toList();
       return _Scored(
         score: _cosineSimilarity(queryEmbedding, emb),
         text: row.content,
       );
-    }).toList()
-      ..sort((a, b) => b.score.compareTo(a.score));
+    }).toList()..sort((a, b) => b.score.compareTo(a.score));
 
     return scored.take(topK).map((s) => s.text).toList();
   }
@@ -92,13 +97,11 @@ class NoteRepositoryImpl implements NoteRepository {
       }
 
       // Split long paragraph by sentence boundaries (.  !  ?)
-      final sentences =
-          p.split(RegExp(r'(?<=[.!?])\s+'));
+      final sentences = p.split(RegExp(r'(?<=[.!?])\s+'));
       var current = '';
 
       for (final sentence in sentences) {
-        final candidate =
-            current.isEmpty ? sentence : '$current $sentence';
+        final candidate = current.isEmpty ? sentence : '$current $sentence';
         if (candidate.length <= maxChars) {
           current = candidate;
         } else {