Add date-range filter for finished jobs

[Shivareddy-Aluri]

Allow filtering completed/finished jobs by a date preset.

• Add date preset UI to Filterable: introduce TEXT_FIELDS, DATE_FIELD and DATE_PRESETS, manage active preset, render date field, and handle keyboard interactions (j/k to cycle, tab/back_tab to change fields). Update filter application/clearing to include date preset state and include the preset label in filter titles and bindings.
• Wire the date range into data queries: add since parameter to Data::JobsQuery.fetch and .count and apply finished_at >= since in fetch_finished and count_finished.
• Update the application to pass the since value when loading/appending finished jobs and update the help text for the filter action.
• Enable the date preset field in the Finished view by overriding filter_fields.

This change makes it possible to view completed jobs limited to common recent time ranges (last hour, 6h, 24h, 7d, 30d, or all time).