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-status-sanitizer.ts

@@ -103,6 +103,7 @@ export function sanitizeDebridAccountStatus(status: DebridAccountStatus, redacti
     accountId: sanitizeAccountStatusText(status.accountId, redactions),
     label: sanitizeAccountStatusText(status.label, redactions),
     maskedLogin: sanitizeAccountStatusText(status.maskedLogin, redactions),
+    username: status.username ? sanitizeAccountStatusText(status.username, redactions) : undefined,
     email: status.email ? sanitizeAccountStatusText(status.email, redactions) : undefined,
     message: sanitizeAccountStatusText(status.message, redactions)
   };