test: cover jobs in Settings, and unpick two shared selectors

The spec worth having is not that the tab is gone -- that is one line
of a table -- but that nothing became unreachable when it went. #24
promises that no action is ever unreachable at any supported size, and
deleting a destination is exactly the change that quietly breaks it.

Two existing selectors had to give. `config-section .header` is
ambiguous the moment a section holds a job, because `job-details-drawer`
carries that class too -- so `settings-reach.spec.ts` locates a
disclosure by role and name instead. And `page-header`'s and
`offline-icons`'s view lists lose an entry each.

Closes #27

frontend/test/components/smoke.test.ts

@@ -40,7 +40,7 @@ import '@components/jobs/job-details-drawer';
 import '@components/jobs/job-indicator';
 import '@components/jobs/job-log-view';
 import '@components/jobs/job-row';
-import '@components/jobs/jobs-view';
+import '@components/jobs/job-panel';
 import '@components/library-filter/library-filter';
 import '@components/library-status-indicator/library-status-indicator';
 import '@components/now-playing/now-playing';
@@ -87,8 +87,8 @@ const TAGS = [
   'job-details-drawer',
   'job-indicator',
   'job-log-view',
+  'job-panel',
   'job-row',
-  'jobs-view',
   'library-filter',
   'library-status-indicator',
   'now-playing',