feat(jira): add editable jira_email field per user

Users can now set a separate Atlassian email for Jira authentication
in Settings → Profile → Jira Integration. Falls back to the Aegis
account email when not set, so existing setups are unaffected.

- Migration b043: adds jira_email column to users table
- User model/schema: expose jira_email read/write
- jira_service: _effective_jira_email() uses jira_email ?? email
- Frontend: replaces read-only email display with editable input

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/pages/SettingsPage.tsx

@@ -816,13 +816,17 @@ function ProfileSection() {
   });
 
   const [jiraAccountId, setJiraAccountId] = useState<string>("");
+  const [jiraEmail, setJiraEmail] = useState<string>("");
   const [jiraApiToken, setJiraApiToken] = useState<string>("");
   const [showToken, setShowToken] = useState(false);
   const [dirty, setDirty] = useState(false);
+  const [initialised, setInitialised] = useState(false);
 
-  // Sync from server on load
-  if (me && !dirty && jiraAccountId === "" && me.jira_account_id) {
+  // Sync from server on first load
+  if (me && !initialised) {
     setJiraAccountId(me.jira_account_id ?? "");
+    setJiraEmail(me.jira_email ?? "");
+    setInitialised(true);
   }
 
   const saveMut = useMutation({
@@ -839,6 +843,7 @@ function ProfileSection() {
   const handleSave = () => {
     const payload: Parameters<typeof updateMyPreferences>[0] = {
       jira_account_id: jiraAccountId || null,
+      jira_email: jiraEmail || null,
     };
     // Only send token if user typed something (empty string clears it)
     if (jiraApiToken !== "") {
@@ -893,14 +898,31 @@ function ProfileSection() {
 
         <div className="border-t border-gray-800 pt-4">
           <p className="text-sm font-semibold text-gray-300 mb-1">Jira Integration (personal settings)</p>
-          <p className="text-xs text-gray-500 mb-4 border-b border-gray-800 pb-3">
-            Auth uses your email:{" "}
-            <span className="text-gray-400 font-medium">
-              {me?.email || "— set email in your profile"}
-            </span>
+          <p className="text-xs text-gray-500 mb-4">
+            Configure your personal Atlassian credentials for Jira integration.
           </p>
 
           <div className="space-y-4">
+            {/* Jira email */}
+            <div>
+              <label className="mb-1 block text-xs font-medium text-cyan-400">
+                Atlassian / Jira Email
+              </label>
+              <input
+                type="email"
+                value={jiraEmail}
+                onChange={(e) => { setJiraEmail(e.target.value); setDirty(true); }}
+                placeholder={me?.email ?? "your@company.com"}
+                className="w-full rounded-lg border border-gray-700 bg-gray-800 px-3 py-2 text-sm text-gray-200 placeholder-gray-600 focus:border-cyan-500 focus:outline-none"
+              />
+              <p className="mt-1 text-xs text-gray-600">
+                Email used to authenticate with Atlassian.
+                {me?.email && !me?.jira_email && (
+                  <span className="text-gray-500"> Currently using Aegis email: <span className="text-gray-400">{me.email}</span></span>
+                )}
+              </p>
+            </div>
+
             {/* API Token */}
             <div>
               <label className="mb-1 block text-xs font-medium text-cyan-400">