fix(jira): honor jira_email override in account-id lookup, not just email

lookup_user_jira_account_id() only ever searched by Aegis login email,
ignoring the jira_email override field that exists precisely for users
whose corporate Atlassian email differs from their Aegis login email
(the rest of jira_service.py already documents and uses this priority
order). Found via jesus-huertas, whose real Jira account uses a
different email than his Aegis account.

backend/app/services/jira_service.py

@@ -295,6 +295,9 @@ def get_admin_jira_client(db: Session):
 def lookup_user_jira_account_id(db: Session, user: User) -> bool:
     """Lookup *user*'s Atlassian account ID by email using the admin Jira client.
 
+    Uses ``user.jira_email`` when set (for users whose corporate Atlassian
+    email differs from their Aegis login email), falling back to
+    ``user.email`` — same resolution order as the rest of this module.
     Updates ``user.jira_account_id`` in-place when found or changed.
     Returns ``True`` when the value was updated, ``False`` otherwise.
     Non-fatal — all errors are logged at DEBUG level and swallowed.
@@ -302,7 +305,7 @@ def lookup_user_jira_account_id(db: Session, user: User) -> bool:
     if not has_admin_jira_configured(db):
         return False
 
-    email = getattr(user, "email", None)
+    email = getattr(user, "jira_email", None) or getattr(user, "email", None)
     if not email:
         return False