fix(jira): report which admin config field is actually missing

POST /system/jira-test bundled 4 independent checks (enabled, url,
admin_email, admin_api_token) behind has_admin_jira_configured() but
always blamed "Admin Email and Admin API Token" regardless of which one
failed. Found via live QA: URL/email/token were all correctly saved, but
the "Enable Jira Integration" toggle was never switched on — the error
message pointed at the wrong fields, making it look like the already-set
credentials were missing.

backend/tests/test_jira_test_connection.py

@@ -0,0 +1,54 @@
+"""Tests for POST /system/jira-test's diagnostic message.
+
+Regression coverage for a real QA-reported bug: has_admin_jira_configured()
+bundles four independent checks (enabled, url, admin_email, admin_api_token)
+into one bool, but the error message always blamed "Admin Email and Admin
+API Token" regardless of which check actually failed. An admin who had set
+url/email/token correctly but never flipped the "Enable Jira Integration"
+toggle saw a misleading message pointing at the wrong fields.
+"""
+
+from app.models.system_config import SystemConfig
+
+
+def _set_config(db, key, value):
+    db.add(SystemConfig(key=key, value=value))
+
+
+def test_jira_test_reports_disabled_toggle_specifically(client, db, auth_headers):
+    """url/email/token all set, but jira.enabled is missing entirely —
+    the message must call out the toggle, not email/token."""
+    _set_config(db, "jira.url", "https://example.atlassian.net")
+    _set_config(db, "jira.admin_email", "admin@example.com")
+    _set_config(db, "jira.admin_api_token", "some-real-token")
+    db.commit()
+
+    resp = client.post("/api/v1/system/jira-test", headers=auth_headers)
+    assert resp.status_code == 200
+    body = resp.json()
+    assert body["status"] == "error"
+    assert "not enabled" in body["message"]
+    assert "Admin Email" not in body["message"]
+    assert "Admin API Token" not in body["message"]
+
+
+def test_jira_test_reports_missing_email_and_token_when_actually_missing(client, db, auth_headers):
+    _set_config(db, "jira.url", "https://example.atlassian.net")
+    _set_config(db, "jira.enabled", "true")
+    db.commit()
+
+    resp = client.post("/api/v1/system/jira-test", headers=auth_headers)
+    assert resp.status_code == 200
+    body = resp.json()
+    assert body["status"] == "error"
+    assert "Admin Email is not set" in body["message"]
+    assert "Admin API Token is not set" in body["message"]
+    assert "not enabled" not in body["message"]
+
+
+def test_jira_test_missing_url_reports_url_specifically(client, db, auth_headers):
+    resp = client.post("/api/v1/system/jira-test", headers=auth_headers)
+    assert resp.status_code == 200
+    body = resp.json()
+    assert body["status"] == "error"
+    assert "Jira URL is not configured" in body["message"]