Fix Apple Shortcuts failing after iCloud sync between devices

[timbms]

Summary

Fixes #1125

Shortcuts created on one device fail on another with "Invalid home: the value provided for home in Get Item State was invalid" after iCloud sync.

Root cause: OpenHABHome.identifier stored a device-local UUID. UUIDs are generated independently on each device, so the UUID stored in a synced shortcut has no match in the second device's storedHomes.

Fix: Replace the UUID with a stable cross-device identifier derived from the home's connection configuration:

Home type	Identifier used
myopenhab.org	cloudUserId (unique per cloud account)
Self-hosted with remote URL	Remote connection URL
Local-only	Local connection URL
Demo / no URLs	UUID (no cross-device benefit, but avoids regression)

This identifier is identical on every device configured for the same openHAB server, so iCloud-synced shortcuts resolve correctly without any user action.

Migration: Shortcuts created before this fix stored a UUID. The lookup now falls back to UUID matching transparently on first run, then Shortcuts saves the new stable identifier format going forward — no user intervention needed.

Changes

• OpenHABIntentHelper: new stableIdentifier(for:) and resolveHomeId(for:) helpers; updated resolveHome, getHomeOptions, and getAllItems to use them
• All 7 intent handlers: replaced direct Preferences.shared.storedHomes[UUID] lookup with resolveHomeId(for:), which handles both new and legacy identifier formats

Test plan

• Create a shortcut using a Get/Set item action on Device A, confirm it works
• Sync to Device B via iCloud, confirm it runs without "Invalid home" error
• Confirm shortcuts created before this fix (UUID-based) still work on the original device
• Confirm shortcuts created before this fix work on a second device after sync (legacy UUID migration path)