fix(accounts): separate Debrid-Link username and email

Persist the username and email returned by the Debrid-Link account endpoint as distinct identity fields and project them into their matching account-table columns. Migrate cached legacy statuses that stored a username in the email field, preserve both fields through renderer validation and sanitization, and cover API responses with and without an email address.

src/main/account-check.ts

@@ -245,15 +245,17 @@ export async function checkDebridLinkKey(
     const premiumLeftSec = Number(value.premiumLeft || 0);
     const accountType = Number(value.accountType || 0);
     const premiumUntilMs = Number.isFinite(premiumLeftSec) && premiumLeftSec > 0 ? now + premiumLeftSec * 1000 : 0;
-    const isPremium = premiumUntilMs > now || accountType > 0;
-    const username = String(value.username || "").trim() || undefined;
-    return {
-      ...base,
-      valid: true,
-      isPremium,
-      premiumUntilMs: premiumUntilMs > 0 ? premiumUntilMs : (accountType > 0 ? null : 0),
-      email: username,
-      message: premiumUntilMs > 0
+    const isPremium = premiumUntilMs > now || accountType > 0;
+    const username = String(value.username || "").trim() || undefined;
+    const email = String(value.email || "").trim() || undefined;
+    return {
+      ...base,
+      valid: true,
+      isPremium,
+      premiumUntilMs: premiumUntilMs > 0 ? premiumUntilMs : (accountType > 0 ? null : 0),
+      username,
+      email,
+      message: premiumUntilMs > 0
         ? formatRemaining(premiumUntilMs, now)
         : (accountType > 0 ? "Premium aktiv" : "Kein Premium (Free)")
     };