feat(server/cron): add allowExpiredTasks to execute overdue tasks

[st860923]

Introduces a new allowExpiredTasks option for cron jobs, allowing scheduled tasks
to execute even if their scheduled time has already passed.

Previously, tasks that were slightly overdue (due to server hitches or thread
delays) were skipped, leading to inconsistencies in scheduling. With this change,
if allowExpiredTasks = true, tasks can still execute when overdue.

Changes:

• Added allowExpiredTasks as an optional parameter in lib.cron.new.

[thelindat]

Not really a suitable fix.

@juddisjudd Do you think we can remove this check outright now? It was there to cover for some edge cases where jobs were incorrectly scheduled.

[juddisjudd]

Not really a suitable fix.

@juddisjudd Do you think we can remove this check outright now? It was there to cover for some edge cases where jobs were incorrectly scheduled.

I will take a look and see what would be best for this.

[juddisjudd]

@thelindat I think maybe this would be a better approach:
Add a maxDelay option:
---@field maxDelay? number Maximum allowed delay in seconds before skipping (default: 0)

if sleep < 0 then
    if not self.maxDelay or -sleep > self.maxDelay then
        return self:stop(self.debug and ('scheduled time expired %s seconds ago'):format(-sleep))
    end
    
    if self.debug then
        print(('Task %s is delayed by %s seconds, executing now'):format(self.id, -sleep))
    end
    
    sleep = 0
end

Example usage then setting something like this:
maxDelay = 30 for a 30 second grace period or something

[thelindat]

Sure we can go with that, maybe default to 1 second.

While we're at it, it would be good to swap to lib.print.debug and default debug to true if printLevel is set to debug. See #593

[juddisjudd]

@st860923 would you like to update your PR with my suggestion or would you prefer that I do this?

[st860923]

You can proceed with your suggested approach. Thank you!