esp32s3: use TIMG0 alarm interrupt for sleepTicks

Replace the busy-wait sleepTicks with an interrupt-driven version that
sets a TIMG0 timer alarm and waits for the interrupt to fire. The timer
alarm handler disables INT_ENA at the peripheral level to prevent
level-triggered re-assertion; sleepTicks re-enables it after each wake.

This avoids burning CPU cycles during time.Sleep and similar delays.

src/runtime/runtime_esp32s3.go

@@ -80,6 +80,9 @@ func main() {
 	// Set up the Xtensa interrupt vector table.
 	interruptInit()
 
+	// Initialize timer alarm interrupt for the scheduler.
+	initTimerInterrupt()
+
 	// Initialize the heap, call main.main, etc.
 	run()