feat(bench): a run keeps its own log; the uninstaller lists items

Two commits, one per issue.

• #33 (closed), a run keeps its own log. When a run's job ends, it copies its log into the run's job-logs/<job>.log on the shared disk, beside report.html. The Log pane reads that copy when this bench has no job for the run, so the log survives an uninstall and can be read from another bench. Runs measured before this change have no copy.
• #34 (closed), the uninstaller lists items. plesty-server purge --list now names one item per module, fleet, device configuration and log kind, plus runs:<experiment> for runs kept in the home, and purge accepts those names. The Windows uninstaller shows them as a tree checklist with sizes, built from purge --list --tsv. When the application no longer starts, the four-box form is the fallback.
• Fixed in #34 (closed): the uninstall form used TSetupForm.Create(nil), which compiles but raises "Resource TSetupForm not found" every time it runs. So no uninstall had ever shown its form, only the yes/no fallback. It now uses CreateCustomForm, and the reason for any fallback goes to uninstall.log. probes/probe3.iss reproduces both behaviours.

Tested on Windows with TEST 0.4.4.dev18 (955b82f0, same content): the checklist was shown, ticking one item removed only that item, and a run's log was kept.