feat(auth): add proxy support and pass ip/user-agent to login

- add ZEN_TRUST_PROXY env variable in .env.example for reverse proxy config
- replace getClientIp() with getIpFromHeaders() using next/headers for ip resolution
- forward ipAddress and userAgent to login action for session tracking

src/features/auth/actions.js

@@ -121,7 +121,8 @@ export async function loginAction(formData) {
     const botCheck = validateAntiBotFields(formData);
     if (!botCheck.valid) return { success: false, error: botCheck.error };
 
-    const ip = await getClientIp();
+    const h = await headers();
+    const ip = getIpFromHeaders(h);
     const rl = enforceRateLimit(ip, 'login');
     if (rl && !rl.allowed) {
       return { success: false, error: `Trop de tentatives. Réessayez dans ${formatRetryAfter(rl.retryAfterMs)}.` };
@@ -129,8 +130,8 @@ export async function loginAction(formData) {
 
     const email = formData.get('email');
     const password = formData.get('password');
-
-    const result = await login({ email, password });
+    const userAgent = h.get('user-agent') || null;
+    const result = await login({ email, password }, { ipAddress: ip !== 'unknown' ? ip : null, userAgent });
 
     // An HttpOnly cookie is the only safe transport for session tokens; setting it
     // here keeps the token out of any JavaScript-readable response payload.