Protect the DeviceRegistry.deleted_devices container

[emontnemery]

Proposed change

Protect the DeviceRegistry.deleted_devices container

Unlike #179578 which protects the devices container, there's no valid public use of the container, and all accesses to DeviceRegistry.deleted_devices from core or core integrations raise and logs a warning from custom integrations.

Needs #179718 +#179719

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:
• Link to developer documentation pull request:
• Link to frontend pull request:

Checklist

• I understand the code I am submitting and can explain how it works.
• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• I have followed the perfect PR recommendations
• The code has been formatted using Ruff (ruff format homeassistant tests)
• Tests have been added to verify that the new code works.
• Any generated code has been carefully reviewed for correctness and compliance with project standards.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies a diff between library versions and ideally a link to the changelog/release notes is added to the PR description.

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.

[Copilot]

Pull request overview

Protects the internal deleted-device registry while providing a deprecation path for custom integrations.

Changes:

• Adds caller-specific deprecation reporting.
• Migrates internal and test access to _deleted_devices.
• Tests core and custom integration behavior.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
homeassistant/helpers/device_registry.py	Protects the deleted-device container.
tests/helpers/test_device_registry.py	Updates access and adds deprecation tests.
tests/common.py	Updates registry test setup.

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[arturpragacz]

There are conflicts.

Other than that looks good.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.