Prise en compte du langage de l'utilisateur pour le prompt de réponse. Si par exemple l'interface est en anglais, les IA vont favoriser l'anglais pour la réponse

web/src/app/interceptors/language.interceptor.ts

@@ -0,0 +1,18 @@
+import { HttpInterceptorFn } from '@angular/common/http';
+import { inject } from '@angular/core';
+import { LanguageService } from '../services/language.service';
+
+/**
+ * Ajoute l'entête `X-User-Language` (langue choisie dans l'UI : `fr`/`en`) à
+ * toutes les requêtes HttpClient. Le Core la relaie au Brain, qui rédige alors
+ * ses réponses IA dans cette langue.
+ *
+ * NB : les appels SSE en `fetch()` (chat, imports, notebooks) ne passent PAS par
+ * les intercepteurs Angular — ils ajoutent l'entête manuellement de leur côté.
+ */
+export const languageInterceptor: HttpInterceptorFn = (req, next) => {
+  const language = inject(LanguageService);
+  return next(
+    req.clone({ setHeaders: { 'X-User-Language': language.current } })
+  );
+};

web/src/app/services/ai-chat.service.ts

@@ -1,6 +1,7 @@
 import { Injectable, inject } from '@angular/core';
 import { Observable } from 'rxjs';
 import { TranslateService } from '@ngx-translate/core';
+import { LanguageService } from './language.service';
 
 /**
  * Un message d'une conversation IA (vue front).
@@ -47,6 +48,7 @@ export type NarrativeEntityType = 'arc' | 'chapter' | 'scene' | 'character' | 'n
 @Injectable({ providedIn: 'root' })
 export class AiChatService {
   private readonly translate = inject(TranslateService);
+  private readonly language = inject(LanguageService);
   private readonly loreEndpoint = '/api/ai/chat/stream';
   private readonly campaignEndpoint = '/api/ai/chat/stream-campaign';
   private readonly sessionEndpoint = '/api/ai/chat/stream-session';
@@ -110,7 +112,8 @@ export class AiChatService {
         method: 'POST',
         headers: {
           'Content-Type': 'application/json',
-          'Accept': 'text/event-stream'
+          'Accept': 'text/event-stream',
+          'X-User-Language': this.language.current
         },
         body: JSON.stringify(body),
         signal: controller.signal

web/src/app/services/campaign-import.service.ts

@@ -7,6 +7,7 @@ import {
   CampaignImportProposal,
   CampaignImportStreamEvent
 } from './campaign-import.model';
+import { LanguageService } from './language.service';
 
 /**
  * Service HTTP pour l'import d'un PDF de campagne.
@@ -17,7 +18,7 @@ import {
  */
 @Injectable({ providedIn: 'root' })
 export class CampaignImportService {
-  constructor(private http: HttpClient, private translate: TranslateService) {}
+  constructor(private http: HttpClient, private translate: TranslateService, private language: LanguageService) {}
 
   importStructureStream(campaignId: string, file: File): Observable<CampaignImportStreamEvent> {
     return new Observable<CampaignImportStreamEvent>((subscriber) => {
@@ -27,7 +28,7 @@ export class CampaignImportService {
 
       fetch(`/api/campaigns/${campaignId}/import-structure/stream`, {
         method: 'POST',
-        headers: { 'Accept': 'text/event-stream' },
+        headers: { 'Accept': 'text/event-stream', 'X-User-Language': this.language.current },
         body: form,
         signal: controller.signal
       })

web/src/app/services/game-system.service.ts

@@ -3,6 +3,7 @@ import { HttpClient, HttpParams } from '@angular/common/http';
 import { Observable } from 'rxjs';
 import { TranslateService } from '@ngx-translate/core';
 import { GameSystem, GameSystemCreate, RulesImportResponse, RulesImportStreamEvent } from './game-system.model';
+import { LanguageService } from './language.service';
 
 /**
  * Service HTTP pour les GameSystems (systèmes de JDR).
@@ -11,7 +12,7 @@ import { GameSystem, GameSystemCreate, RulesImportResponse, RulesImportStreamEve
 export class GameSystemService {
   private apiUrl = '/api/game-systems';
 
-  constructor(private http: HttpClient, private translate: TranslateService) {}
+  constructor(private http: HttpClient, private translate: TranslateService, private language: LanguageService) {}
 
   getAll(): Observable<GameSystem[]> {
     return this.http.get<GameSystem[]>(this.apiUrl);
@@ -63,7 +64,7 @@ export class GameSystemService {
 
       fetch(`${this.apiUrl}/import-rules/stream`, {
         method: 'POST',
-        headers: { 'Accept': 'text/event-stream' },
+        headers: { 'Accept': 'text/event-stream', 'X-User-Language': this.language.current },
         body: form,
         signal: controller.signal
       })

web/src/app/services/notebook.service.ts

@@ -3,6 +3,7 @@ import { HttpClient } from '@angular/common/http';
 import { Observable } from 'rxjs';
 import { TranslateService } from '@ngx-translate/core';
 import { Notebook, NotebookArchive, NotebookDetail, NotebookSource, NotebookChatEvent } from './notebook.model';
+import { LanguageService } from './language.service';
 
 /**
  * Service des notebooks (atelier RAG) : CRUD, upload/indexation de sources,
@@ -12,7 +13,7 @@ import { Notebook, NotebookArchive, NotebookDetail, NotebookSource, NotebookChat
 export class NotebookService {
   private readonly apiUrl = '/api/notebooks';
 
-  constructor(private http: HttpClient, private zone: NgZone, private translate: TranslateService) {}
+  constructor(private http: HttpClient, private zone: NgZone, private translate: TranslateService, private language: LanguageService) {}
 
   listByCampaign(campaignId: string): Observable<Notebook[]> {
     return this.http.get<Notebook[]>(`${this.apiUrl}/campaign/${campaignId}`);
@@ -73,7 +74,7 @@ export class NotebookService {
         try {
           const response = await fetch(`${this.apiUrl}/${notebookId}/chat/stream`, {
             method: 'POST',
-            headers: { 'Content-Type': 'application/json', 'Accept': 'text/event-stream' },
+            headers: { 'Content-Type': 'application/json', 'Accept': 'text/event-stream', 'X-User-Language': this.language.current },
             credentials: 'include',
             body: JSON.stringify({
               message, deep,