fix(audit): prototypes Gemini server-side + retire metrics-token du dépôt

Proxy Gemini côté serveur (plus de clé dans le bundle Vite), port prototype 4000,
et suppression du token métriques placeholder versionné.

Co-authored-by: Cursor <cursoragent@cursor.com>

architectural-grid1/src/services/geminiService.ts

@@ -2,7 +2,24 @@
 import { GoogleGenAI, Type } from "@google/genai";
 import { BrainstormIdea } from "../types";
 
-const ai = new GoogleGenAI({ apiKey: process.env.GEMINI_API_KEY });
+async function generateContent(
+  request: Parameters<InstanceType<typeof GoogleGenAI>['models']['generateContent']>[0],
+) {
+  if (typeof window !== 'undefined') {
+    const res = await fetch('/api/gemini/generate', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(request),
+    });
+    if (!res.ok) throw new Error('Gemini request failed');
+    const data = await res.json();
+    return { text: data.text ?? '' };
+  }
+  const key = process.env.GEMINI_API_KEY;
+  if (!key) throw new Error('GEMINI_API_KEY required on server');
+  const ai = new GoogleGenAI({ apiKey: key });
+  return ai.models.generateContent(request);
+}
 
 const BRAINSTORM_SCHEMA = {
   type: Type.OBJECT,
@@ -63,7 +80,7 @@ export async function generateBrainstormWave(
   `;
 
   try {
-    const response = await ai.models.generateContent({
+    const response = await generateContent({
       model: "gemini-3-flash-preview",
       contents: [{ role: "user", parts: [{ text: prompt }] }],
       config: {
@@ -101,7 +118,7 @@ export async function generateExpansion(parentIdeaTitle: string, parentIdeaDescr
   `;
 
   try {
-    const response = await ai.models.generateContent({
+    const response = await generateContent({
       model: "gemini-3-flash-preview",
       contents: [{ role: "user", parts: [{ text: prompt }] }],
       config: {
@@ -130,9 +147,27 @@ export async function generateExpansion(parentIdeaTitle: string, parentIdeaDescr
   }
 }
 
+async function embedContent(
+  request: Parameters<InstanceType<typeof GoogleGenAI>['models']['embedContent']>[0],
+) {
+  if (typeof window !== 'undefined') {
+    const res = await fetch('/api/gemini/embed', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(request),
+    });
+    if (!res.ok) throw new Error('Gemini embed failed');
+    return res.json();
+  }
+  const key = process.env.GEMINI_API_KEY;
+  if (!key) throw new Error('GEMINI_API_KEY required on server');
+  const ai = new GoogleGenAI({ apiKey: key });
+  return ai.models.embedContent(request);
+}
+
 export async function getEmbedding(text: string): Promise<number[]> {
   try {
-    const result = await ai.models.embedContent({
+    const result = await embedContent({
       model: 'gemini-embedding-2-preview',
       contents: [text],
     });
@@ -155,7 +190,7 @@ export function cosineSimilarity(a: number[], b: number[]): number {
 export async function nameCluster(noteSummaries: string[]): Promise<string> {
   const prompt = `Quel thème commun relie ces notes ? Donne un nom court (2-4 mots).\nNotes :\n${noteSummaries.join('\n- ')}`;
   try {
-    const result = await ai.models.generateContent({
+    const result = await generateContent({
       model: "gemini-3-flash-preview",
       contents: prompt
     });
@@ -184,7 +219,7 @@ export async function suggestBridgeIdeas(
   `;
 
   try {
-    const response = await ai.models.generateContent({
+    const response = await generateContent({
       model: "gemini-3-flash-preview",
       contents: prompt,
       config: {
@@ -207,7 +242,7 @@ export async function parseDocument(fileUrl: string, fileName: string): Promise<
   try {
     // In a real scenario, we would use media upload. 
     // Here we simulate the extraction. 
-    const response = await ai.models.generateContent({
+    const response = await generateContent({
       model: "gemini-3-flash-preview",
       contents: [{ role: "user", parts: [{ text: prompt }] }],
       config: {
@@ -236,7 +271,7 @@ export async function extractActionItems(notes: { title: string; content: string
   `;
 
   try {
-    const response = await ai.models.generateContent({
+    const response = await generateContent({
       model: "gemini-3-flash-preview",
       contents: prompt,
       config: {
@@ -289,7 +324,7 @@ export async function generateFlashcardsForNote(
   `;
 
   try {
-    const response = await ai.models.generateContent({
+    const response = await generateContent({
       model: "gemini-3.5-flash",
       contents: [{ role: "user", parts: [{ text: prompt }] }],
       config: {