[feature] Add "Start monitoring from date" field to auto-unpause watches

[Elberius]

When monitoring content that will only become relevant at a future date, some need a way to schedule when monitoring should begin.

Examples:

• TV show season premieres (start checking 1 week before air date)
• Product launches (start monitoring on announcement date)
• Event pages (start checking closer to the event)
• Scheduled content releases

Solution is to add an optional "Start monitoring from" date field in the General tab that:

• Keeps the watch paused until the specified date
• Automatically unpauses and begins checking on that date
• Shows the scheduled start date in the watch list (perhaps with a calendar icon)
• Clears itself after activation (or optionally could be recurring yearly)

Current workaround

1. Pause the watch manually
2. Set a personal reminder to unpause it
3. Manually unpause when the date arrives
4. Or use external automation via API + cron jobs, which adds complexity.

[dgtlmoon]

Nice idea, tho i think it would be better solved as a condition #3244

[dgtlmoon]

OR less work and easier to understand is to add a date field to the scheduler

which would make more sense

[dgtlmoon]

Maybe an icon to show it's running/restricted by scheduler too