[manuelmayer-dev]

Closes #1022

Summary

Plugins can return false from IConfigFlowProvider.RequiresConfiguration, so a config flow that only holds optional settings no longer disables the integration or marks it as needing setup. The flag travels in the config-flow describe payload, and the setup flows guide documents the zero-entry state.

Testing

Release build and full test suites pass, with new host, protocol, SDK, plugin contract and desktop UI tests, including old-plugin payloads without the field. Verified against a disposable host with a scratch plugin: without an entry it runs and its actions are Ready, saving and removing the settings reinitializes it, and the detail page shows Ready.

Plugin SDK / API compatibility

• No public, non-obsolete SDK or plugin protocol contract was removed or changed
• Contracts were only extended additively (new members with defaults, new optional fields, new message types)
• Anything being retired carries [Obsolete] and [MacroDeckDeprecated], is in the deprecation registry, and still works
• A plugin compiled against the previous SDK still loads and behaves identically (source and binary compatible)
• The conformance suite passes and the sample plugin builds and runs unchanged
• Any intentional break was explicitly agreed beforehand and is described below

Checklist

• Tests were added or updated where needed
• The change was verified manually where appropriate
• Documentation was updated if the change affects documented behaviour
• I reviewed and understand every submitted change