Web dashboard step 6: jobs and stats

Job catalogue and daily-epub job run, the systemd job unit and polkit rule,
SystemdRunner/MockRunner, the Jobs pages with status and journal tail, the
stats_data refactor with a byte-identical CLI, the stats page and the
overview sparklines.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NHyYupFdBiR4VfoUM7NjSM

src/web/static/app.js

@@ -57,3 +57,8 @@ document.querySelectorAll("table[data-filter]").forEach((table) => {
     });
   });
 });
+/* step 6: reload a job page every N seconds while its job is requested/running */
+document.querySelectorAll("[data-refresh]").forEach((element) => {
+  const seconds = Number(element.dataset.refresh);
+  if (seconds > 0) setTimeout(() => window.location.reload(), seconds * 1000);
+});