Rename timer last_action to last_transition

[emontnemery]

Proposed change

Rename timer last_action to last_transition

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:
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• 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.
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• Tests have been added to verify that the new code works.
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[emontnemery]

I'm not sure this is understandable?

[MartinHjelmare]

I think it's good. It's better than last action as we didn't include all actions in last action.

[Copilot]

Pull request overview

This PR renames the Timer entity state attribute last_action to last_transition in the timer integration, updating the integration code, tests, and UI strings accordingly.

Changes:

• Renamed the timer attribute constant and internal field from last_action to last_transition.
• Updated timer tests to assert on last_transition instead of last_action.
• Added translation strings for the new last_transition state attribute (including value labels like started/paused/etc).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
homeassistant/components/timer/__init__.py	Renames the exposed state attribute and the internal tracking field to last_transition, and updates restore logic accordingly.
homeassistant/components/timer/strings.json	Adds translated name + value labels for the new last_transition attribute.
tests/components/timer/test_init.py	Updates all assertions and a couple of test names/docstrings to use last_transition.

[emontnemery]

The bot comments about this being a breaking change are technically correct, but the last_action state attribute has only been on dev for a couple of hours so we don't need to treat it as breaking.