Problem

Collection schedule defaults are set in `install/04_create_schedule_table.sql`, which only populates the `config.collection_schedule` table on first install. When we tune the schedule (e.g. bumping cheap collectors from 5-min to 1-min as done in #86), existing users keep the old schedule.

Expected behavior

The installer should offer a way to apply the current recommended schedule to existing installs — either automatically or via an "apply suggested schedule" option.

Possible approaches

• Add an "update schedule" script that MERGEs new defaults (only updates frequency, preserves user overrides like enabled/disabled)
• Add a `config.apply_default_schedule` procedure that resets frequencies to recommended values
• Version the schedule and prompt on install if the current schedule is outdated
• Store user-customized vs default in a separate column so we know what's safe to update

Context

In #86 we tuned the schedule: 18 cheap collectors to 1-min, 4 medium to 2-min. This only applies to new installs.