feat(pricing): remove DeepL from all user-facing surfaces

Pricing: 'deepl' removed from plan provider lists and the comparison
table row. Landing and pricing copy (13 locales) no longer mention
DeepL (65 values cleaned, 39 dead keys deleted: pricing.comparison.deepl,
providerTheme.classic.deepl.*).

Providers: available-provider responses are filtered so a DeepL entry
from the backend can never surface in the engine picker or the services
page; DeepL theme entry and static lib/api.ts list entry removed.

Admin: DeepL config card, type fields, defaults and fallback-chain
mentions removed; stats/chart/status maps and mock data cleaned.

Backend adapter untouched — DeepL is invisible app-wide via the UI
filter; removing the Python adapter itself is a separate step if wanted.

Verified: build exit 0, vitest 9/9, eslint clean on touched files,
zero 'deepl' occurrences outside the two intentional UI filters.

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

@@ -36,7 +36,6 @@ interface SmtpConfig {
 interface SettingsConfig {
   google: ProviderConfig;
   google_cloud: ProviderConfig;
-  deepl: ProviderConfig;
   openai: ProviderConfig;
   ollama: ProviderConfig;
   openrouter: ProviderConfig;
@@ -50,7 +49,6 @@ interface SettingsConfig {
 }
 
 interface EnvInfo {
-  deepl: boolean;
   openai: boolean;
   openrouter: boolean;
   openrouter_premium: boolean;
@@ -70,7 +68,6 @@ 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" },
   openrouter: { enabled: false, api_key: "", model: "deepseek/deepseek-chat" },
@@ -78,13 +75,12 @@ const defaultConfig: SettingsConfig = {
   zai: { enabled: false, api_key: "", base_url: "https://api.x.ai/v1", model: "grok-2-1212" },
   mistral: { enabled: false, api_key: "", model: "mistral-ocr-latest", timeout: 180 },
   smtp: { enabled: false, host: "", port: 587, username: "", password: "", from_email: "", use_tls: true },
-  fallback_chain: "google,google_cloud,deepl,openrouter,openrouter_premium,openai,deepseek,zai",
-  fallback_chain_classic: "google,google_cloud,deepl",
+  fallback_chain: "google,google_cloud,openrouter,openrouter_premium,openai,deepseek,zai",
+  fallback_chain_classic: "google,google_cloud",
   fallback_chain_llm: "openrouter,openrouter_premium,openai,deepseek,zai",
 };
 
 const defaultEnvInfo: EnvInfo = {
-  deepl: false,
   openai: false,
   openrouter: false,
   openrouter_premium: false,
@@ -366,28 +362,6 @@ export default function AdminSettingsPage() {
           </div>
         </ProviderCard>
 
-        <ProviderCard
-          title="DeepL"
-          description="Traduction professionnelle. Obtenez une clé sur deepl.com/pro-api"
-          enabled={config.deepl.enabled}
-          onToggle={(enabled) => updateProvider("deepl", { enabled })}
-          onTest={() => testProvider("deepl")}
-          testResult={testResults.deepl ?? "idle"}
-          testMessage={testMessages.deepl}
-          envKeySet={envInfo.deepl}
-        >
-          <div className="space-y-2">
-            <Label htmlFor="deepl-key">Clé API</Label>
-            <Input
-              id="deepl-key"
-              type="password"
-              placeholder={envInfo.deepl ? "Clé configurée dans .env (laisser vide pour l'utiliser)" : "Entrez votre clé DeepL"}
-              value={config.deepl.api_key || ""}
-              onChange={(e) => updateProvider("deepl", { api_key: e.target.value })}
-            />
-          </div>
-        </ProviderCard>
-
         <ProviderCard
           title="OpenAI"
           description="Traductions GPT-4. Obtenez une clé sur platform.openai.com"
@@ -655,11 +629,11 @@ export default function AdminSettingsPage() {
           </CardHeader>
           <CardContent className="space-y-4">
             <div className="space-y-2">
-              <Label>Mode classique (Google/DeepL)</Label>
+              <Label>Mode classique (Google)</Label>
               <Input
                 value={config.fallback_chain_classic}
                 onChange={(e) => setConfig((prev) => ({ ...prev, fallback_chain_classic: e.target.value }))}
-                placeholder="google,deepl"
+                placeholder="google,google_cloud"
               />
             </div>
             <div className="space-y-2">