Prepare v1.1.0-rc1 with an opt-in Home Assistant Beta add-on - #85

Prepare v1.1.0-rc1 so volunteers can test the merged V2 key-recovery changes from #84 through Home Assistant. The existing stable add-on stays on 1.0.2; its manifest, settings, and update target are unchanged.

Add Roborock Local Server Beta as a separate, opt-in add-on with its own slug and persistent data. It selects the 1.1.0-rc1 image, is marked experimental, and defaults to manual startup. The setup guide explains the initial configuration/cloud import, shared-port handling, later Beta updates, and returning to stable. Complete V2 onboarding and MQTT connectivity still need hardware validation.

Synchronize the package/module version and lockfile, and make the version checks distinguish stable from prerelease add-ons. Prerelease publishing explicitly excludes the latest, major, and minor image aliases, using both the GitHub prerelease flag and the tag suffix.

Validation:

• 43 version, HA add-on, container-entrypoint, configuration, and setup tests passed.
• Source distribution and wheel built successfully; Python normalizes the package version to 1.1.0rc1.
• The existing release workflow's version-validation script passed for v1.1.0-rc1.
• Strict documentation build and git diff --check passed.
• Verified the entire stable add-on directory is unchanged from origin/main.

After merging, publish a GitHub prerelease tagged v1.1.0-rc1 from the merged commit. Wait for the release workflow to publish ghcr.io/python-roborock/local_roborock_server:1.1.0-rc1 for amd64 and arm64 before directing testers to install Beta. Testers opt in once; subsequent Beta builds use Home Assistant's normal update flow.