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/lib.rs

@@ -23,6 +23,7 @@ pub mod extract;
 pub mod html;
 pub mod http;
 pub mod images;
+pub mod jobs;
 pub mod lock;
 pub mod miniflux;
 pub mod pipeline;