feat(scheduling,admin,today): week-range queries, file size limits, mobile nav UX

- Expand exceptional application query to Monday of start week
- Add 20MB file size limit with visual feedback in ImageUpload
- Reorder admin nav links, add burger badge, slide transition + backdrop
- Fetch week-range working/available hours, add closing time indicator
- Skip lunch protection for days <= 5h via shouldApplyLunchProtection
- Extract formatDateISO to shared utils

frontend/src/lib/lunchProtection.ts

@@ -133,6 +133,15 @@ export function findLargestLunchGap(
 export const LUNCH_MINIMUM_USER = 60;
 export const LUNCH_MINIMUM_ADMIN = 30;
 export const LUNCH_WARNING_THRESHOLD = 60;
+export const LUNCH_MIN_DAY_DURATION = 5 * 60; // 300 minutes — skip lunch for days ≤ 5h
+
+/**
+ * Check lunch protection should apply at all for a day of this duration
+ */
+export function shouldApplyLunchProtection(dayStartTime: string, dayEndTime: string): boolean {
+	const dayDuration = timeToMinutes(dayEndTime) - timeToMinutes(dayStartTime);
+	return dayDuration > LUNCH_MIN_DAY_DURATION;
+}
 
 /**
  * Check if a proposed booking slot violates lunch protection
@@ -145,6 +154,9 @@ export function checkLunchProtection(
 	proposedSlotEnd: string,
 	isAdmin: boolean
 ): LunchProtectionResult {
+	if (!shouldApplyLunchProtection(dayStartTime, dayEndTime)) {
+		return { isBlocked: false, showWarning: false };
+	}
 	const { windowStart, windowEnd } = calculateMiddleWindow(dayStartTime, dayEndTime);
 
 	const windowDuration = windowEnd - windowStart;
@@ -288,6 +300,10 @@ export function getLunchProtectionForSlots(
 		return results;
 	}
 
+	if (!shouldApplyLunchProtection(dayStartTime, dayEndTime)) {
+		return results;
+	}
+
 	const dayStartMinutes = timeToMinutes(dayStartTime);
 	const dayEndMinutes = timeToMinutes(dayEndTime);