fix(data): race-safe DB open, graceful unknown types, explicit id error + fallback tests

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/data/dto/pokemon_dto.dart

@@ -32,7 +32,9 @@ class PokemonDto {
   /// Construit une entité depuis la réponse Tyradex (objet unique ou élément de liste).
   /// [fallbackId] sert quand le JSON ne contient pas `pokedex_id`.
   static Pokemon fromTyradexJson(Map<String, dynamic> json, {int? fallbackId}) {
-    final id = (json['pokedex_id'] as int?) ?? fallbackId!;
+    final id = (json['pokedex_id'] as int?) ??
+        fallbackId ??
+        (throw ArgumentError('pokedex_id absent et fallbackId non fourni'));
     final nameMap = json['name'] as Map<String, dynamic>?;
     final name = nameMap?['fr'] ?? nameMap?['en'] ?? 'unknown';
 
@@ -77,9 +79,15 @@ class PokemonDto {
     return Pokemon(
       name: row['name'],
       id: row['id'],
-      type1: PokemonType.values.firstWhere((e) => e.name == row['type1']),
+      type1: PokemonType.values.firstWhere(
+        (e) => e.name == row['type1'],
+        orElse: () => PokemonType.unknown,
+      ),
       type2: row['type2'] != null
-          ? PokemonType.values.firstWhere((e) => e.name == row['type2'])
+          ? PokemonType.values.firstWhere(
+              (e) => e.name == row['type2'],
+              orElse: () => PokemonType.unknown,
+            )
           : null,
       hp: row['hp'] ?? 0,
       atk: row['atk'] ?? 0,