Portal: add reusable 12-hour TimeInput component

TimeInput displays and accepts AM/PM times, offers the 5-minute options as
suggestions, and allows typing any minute 00-59; its value model is a 24h
HH:MM string. Adds isomorphic parseTimeInput/hmToMinutes/fiveMinuteOptions
helpers and unit + component tests for them.

src/lib/schedule-utils.ts

@@ -45,6 +45,62 @@ export function toHm(minutes: number): string {
 	return `${String(hours).padStart(2, '0')}:${String(mins).padStart(2, '0')}`;
 }
 
+/**
+ * Parse a 24-hour `HH:MM` string into minutes from midnight. Returns null when
+ * the input is not a valid 24-hour time.
+ */
+export function hmToMinutes(hm: string): number | null {
+	const match = /^(\d{2}):(\d{2})$/.exec(hm.trim());
+	if (!match) return null;
+	const hours = Number(match[1]);
+	const minutes = Number(match[2]);
+	if (hours > 23 || minutes > 59) return null;
+	return hours * 60 + minutes;
+}
+
+export type TimeInputResult = { ok: true; minutes: number } | { ok: false; error: string };
+
+/**
+ * Parse a user-typed 12-hour clock time into minutes from midnight. Tolerant of
+ * "7:05 pm", "7:05PM", "7pm", "7:7", "12:00 am". A period is optional; when
+ * present the hour must be 1-12, so "13:00 PM" is rejected. Minutes may be any
+ * value 00-59, not just the 5-minute steps.
+ */
+export function parseTimeInput(raw: string): TimeInputResult {
+	const text = raw.trim().toLowerCase();
+	if (!text) return { ok: false, error: 'Enter a time.' };
+
+	const match = /^(\d{1,2})(?::(\d{1,2}))?\s*(am|pm|a|p)?$/.exec(text);
+	if (!match) return { ok: false, error: 'Enter a time like 7:05 PM.' };
+
+	const hour = Number(match[1]);
+	const minute = match[2] === undefined ? 0 : Number(match[2]);
+	const period = match[3];
+
+	if (minute > 59) return { ok: false, error: 'Minutes must be 00-59.' };
+
+	if (period) {
+		if (hour < 1 || hour > 12) {
+			return { ok: false, error: 'Hour must be 1-12 when AM/PM is given.' };
+		}
+		const isPm = period === 'pm' || period === 'p';
+		const hours24 = (hour % 12) + (isPm ? 12 : 0);
+		return { ok: true, minutes: hours24 * 60 + minute };
+	}
+
+	if (hour > 23) return { ok: false, error: 'Hour must be 0-23.' };
+	return { ok: true, minutes: hour * 60 + minute };
+}
+
+/** The 5-minute clock options (00:00, 00:05, ..., 23:55) in play order. */
+export function fiveMinuteOptions(): number[] {
+	const options: number[] = [];
+	for (let minutes = 0; minutes < MINUTES_PER_DAY; minutes += 5) {
+		options.push(minutes);
+	}
+	return options;
+}
+
 /** Snap a minute value to the nearest `SNAP_MINUTES` interval, clamped to 24h. */
 export function snapMinutes(minutes: number): number {
 	const snapped = Math.round(minutes / SNAP_MINUTES) * SNAP_MINUTES;