feat: production deployment - full update with providers, admin, glossaries, pricing, tests

Major changes across backend, frontend, infrastructure:
- Provider system with model selection (Google, DeepL, OpenAI, Ollama, Google Cloud)
- Admin panel: user management, pricing, settings
- Glossary system with CSV import/export
- Subscription and tier quota management
- Security hardening (rate limiting, API key auth, path traversal fixes)
- Docker compose for dev, prod, and IONOS deployment
- Alembic migrations for new tables
- Frontend: dashboard, pricing page, landing page, i18n (en/fr)
- Test suite and verification scripts

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/app/admin/settings/page.tsx

@@ -24,6 +24,7 @@ interface ProviderConfig {
 
 interface SettingsConfig {
   google: ProviderConfig;
+  google_cloud: ProviderConfig;
   deepl: ProviderConfig;
   openai: ProviderConfig;
   ollama: ProviderConfig;
@@ -42,6 +43,7 @@ interface EnvInfo {
   openrouter_premium: boolean;
   zai: boolean;
   ollama: boolean;
+  google_cloud: boolean;
 }
 
 interface OllamaModel {
@@ -52,6 +54,7 @@ interface OllamaModel {
 
 const defaultConfig: SettingsConfig = {
   google: { enabled: true, timeout: 30, max_retries: 3 },
+  google_cloud: { enabled: false, api_key: "", timeout: 30, max_retries: 3 },
   deepl: { enabled: false, api_key: "", timeout: 30, max_retries: 3 },
   openai: { enabled: false, api_key: "", timeout: 60, max_retries: 3 },
   ollama: { enabled: false, base_url: "http://localhost:11434", model: "llama3" },
@@ -70,6 +73,7 @@ const defaultEnvInfo: EnvInfo = {
   openrouter_premium: false,
   zai: false,
   ollama: false,
+  google_cloud: false,
 };
 
 export default function AdminSettingsPage() {
@@ -224,7 +228,7 @@ export default function AdminSettingsPage() {
       <div className="grid gap-4">
         <ProviderCard
           title="Google Translate"
-          description="Tier gratuit : 500 000 caractères/mois. Aucune clé requise."
+          description="Accès web non officiel via deep_translator. Aucune clé requise, usage raisonnable recommandé."
           enabled={config.google.enabled}
           onToggle={(enabled) => updateProvider("google", { enabled })}
           onTest={() => testProvider("google")}
@@ -233,6 +237,35 @@ export default function AdminSettingsPage() {
           noApiKey
         />
 
+        <ProviderCard
+          title="Google Cloud Translation (officiel)"
+          description="API officielle Google Cloud. 500 000 car./mois offerts, puis ~$20/M car. Clé API sur console.cloud.google.com"
+          enabled={config.google_cloud.enabled}
+          onToggle={(enabled) => updateProvider("google_cloud", { enabled })}
+          onTest={() => testProvider("google_cloud")}
+          testResult={testResults.google_cloud ?? "idle"}
+          testMessage={testMessages.google_cloud}
+          envKeySet={envInfo.google_cloud}
+        >
+          <div className="space-y-2">
+            <Label htmlFor="google-cloud-key">Clé API</Label>
+            <Input
+              id="google-cloud-key"
+              type="password"
+              placeholder={
+                envInfo.google_cloud
+                  ? "Clé configurée dans .env (laisser vide pour l'utiliser)"
+                  : "AIza..."
+              }
+              value={config.google_cloud.api_key || ""}
+              onChange={(e) => updateProvider("google_cloud", { api_key: e.target.value })}
+            />
+            <p className="text-xs text-muted-foreground">
+              Activez <code>Cloud Translation API</code> dans Google Cloud Console, puis créez une clé API restreinte à cette API.
+            </p>
+          </div>
+        </ProviderCard>
+
         <ProviderCard
           title="DeepL"
           description="Traduction professionnelle. Obtenez une clé sur deepl.com/pro-api"