feat(device): replace daily wakeHour with multi-time wakeTimes (minutes)

Frame settings now offer two update-frequency modes: "at specific times" or
"every X minutes". Times are stored as an int[] of minutes-since-midnight,
allowing multiple slots per day at minute granularity. Backend computes the
earliest upcoming slot for X-Interval-Ms and uses the most-recent-past slot
as the rotation-due boundary. PWA settings sheet has hour/minute/AM-PM
dropdowns with + Add / trash, a live "next update" preview, and a note
that changes only take effect at the device's next sync.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/stores/devices.ts

@@ -26,7 +26,7 @@ export const useDevicesStore = defineStore('devices', () => {
     }
   }
 
-  async function updateDevice(id: number, patch: Partial<Pick<Device, 'name' | 'orientation' | 'rotationIntervalMinutes' | 'wakeHour' | 'timezone' | 'uniquenessWindow'>>) {
+  async function updateDevice(id: number, patch: Partial<Pick<Device, 'name' | 'orientation' | 'rotationIntervalMinutes' | 'wakeTimes' | 'timezone' | 'uniquenessWindow'>>) {
     const res = await fetch(`/api/devices/${id}`, {
       method: 'PATCH',
       headers: { 'Content-Type': 'application/json' },