Predefined timespan

[TheWitness]

No description provided.

[Copilot]

Pull request overview

This PR updates the Syslog plugin’s time filtering to better support a “predefined timespan” vs. custom date range flow, including making “Custom” available as a selectable timespan and adjusting how span/shift/custom selections persist across requests.

Changes:

• Refines syslog_request_validation() / set_shift_span() logic to distinguish predefined span (>0), shift, and custom date ranges, and to restore/compute date1/date2 accordingly.
• Updates the timespan dropdown rendering to include “Custom” and to generate options by iterating the $graph_timespans map.
• Adjusts main filter URL building and datetimepicker behavior in JS (adds seconds; switches timespan to “Custom” when dates are manually changed).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
syslog.php	Updates request validation and span/shift/custom date handling; adjusts timespan dropdown generation.
js/functions.js	Changes how filter URLs are built and improves datetimepicker behavior for custom ranges.