Portal: 12-hour schedule times and dynamicAudio default on

Use TimeInput for Block start/end and show the day timeline axis with
AM/PM, so no 24-hour time is displayed in the schedule UI. New Blocks now
default dynamicAudio to true in the modal and server-side when the field
is absent; existing stored Blocks are untouched.

src/routes/(protected)/(user)/schedule/+page.svelte

@@ -21,7 +21,7 @@
 		initialStart = startMinutes;
 		initialEnd = endMinutes;
 		initialIds = [];
-		initialDynamicAudio = false;
+		initialDynamicAudio = true;
 		modalOpen = true;
 	}