feat: host-drawn countdown, alarm, opening at a deadline

[eugypalu]

Rel to #750

What each issue asked of truapi

• Pill Overlay that hovers across the User Agent #558, the pill. A new surface. Until now a product could draw only inside its own surface.
• Ability to set alarms in the user's device #560, the alarm. Scheduled notifications already existed. What was missing was a way to say that a notification should ring as an alarm.
• Jollity game starts automatically for registered users #559, the automatic start. Opening a product already existed. What was missing was a way to say when to open it.

What a product can do now

• Declare a pill with a key, the instant it appears, a deadline, a destination, a title, and a flag for opening that destination at the deadline.
• Withdraw it by key. The call is idempotent, and declaring again with a live key replaces that declaration.
• Ask for Critical urgency on a scheduled notification, and read back the urgency that was delivered.

What the app still has to do

• Draw the pill and its countdown, persist the declaration across restarts, and hide it while the declaring product is in the foreground.
• Open the destination on tap, and at the deadline when the declaration asks for it.
• Map Critical onto the platform's alarm framework, and refuse the Alarms grant where there is no alarm framework.
• Take HostBridge.pushNotification's new second argument.

[github-actions]

CI Status: not green, 3 items need attention.

• ios-swift: failure
• android-bindings: failure
• ts-host: failure

All job results

job	result
android-bindings	failure
changes	success
changeset-guard	success
codegen	success
e2e	skipped
explorer	success
ios-bindings	success
ios-swift	failure
licenses	success
playground	success
release-guard	success
rust	success
ts-client	success
ts-debugger	success
ts-host	failure
wasm-provider	success
workflow-lint	skipped

_{Commit 85491904 · run log}