feat: Allow device manager to perform rediscovery of devices

[allenporter]

This adds an opton to skip the cache, but also supports fallback to the old device list. Adds tests exercising rediscovery and various cache falblack cases on failure.

We currently never refresh home data once it is loaded, so we need to add a mechanism to discover new devices outside of the cache. This is a first step, and later we'll add automated polling to rediscover deivces.

Discussion in home-assistant/core#158818 has context about the problem.

[Copilot]

Pull request overview

This PR adds the ability to perform device rediscovery by introducing a prefer_cache parameter to the discover_devices() method. When set to False, the device manager will fetch fresh home data from the API instead of using cached data, allowing the system to discover newly added devices. The implementation includes fallback logic to use cached data if the API call fails.

• Added prefer_cache parameter to discover_devices() method (defaults to True for backward compatibility)
• Implemented exception handling with fallback to cached data when API calls fail
• Added comprehensive test coverage for cache logic, fallback behavior, and rediscovery scenarios

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
tests/mock_data.py	Added type annotation to HOME_DATA_RAW for better type safety
tests/devices/test_device_manager.py	Parametrized existing cache test and added new tests for cache fallback and device rediscovery scenarios
roborock/devices/device_manager.py	Modified discover_devices() to support cache bypass with prefer_cache parameter and added exception handling with cache fallback

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.