Update Agent.alarm to readonly, linking to schedule-task docs

[nickfujita]

Since the Agent class has a custom implementation for scheduled tasks via this.schedule, if the alarm class is implemented on a subclass, it doesn't perform as expected. While a quick trip to the docs would point you in this direction, it would be nice to have a ts error and js doc explaining that instead of implementing alarm, use the schedule method instead. Was able to find a solution to provide a type warning in one case, but not sure if there is a better way to do this to catch all cases?

• Updates alarm function on Agent class to be readonly, to produce a ts error on subclasses trying to override this method as an instance member function
• Adds js doc to alarm function with link to schedule-task docs, in the hopes that this steers them in the right direction

Test happy path

• In the AIChatAgent class, add a dummy alarm method

async alarm() {
  console.log('hello');
}

• Produces the following type error

Class 'Agent<Env, State>' defines instance member property 'alarm', but extended class 'AIChatAgent<Env, State>' defines it as instance member function.ts(2425)

• If the code is executed, the alarm function on AIChatAgent shouldn't be called, only the one on Agent

Possible subversion

If the user reads the error they could actually just get around this by instead adding to AIChatAgent

alarm = async () => {
  console.log('hello');
}

So it's not a fool proof solution, but the hope is that it would guard the majority that just follow the cloudflare docs on how to implement alarms.

[changeset-bot]

🦋 Changeset detected

Latest commit: 71d1d27

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
agents	Patch
hono-agents	Patch

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[threepointone]

lgtm, thank you!