Type the Connector family with all 22 children.

[shadyvb]

Part of XWPENG-47 — typed properties rollout for PHP 8.2+.

Adds native PHP type declarations to the Connector abstract base and all 22 built-in connector children so property contracts are enforced at runtime and redundant @var docblocks can be removed.

Approach

• Typed every assignable property on Connector: string $name, array $actions / $delayed, ?int $prev_stream, bool $register_admin / $register_frontend, and private bool $is_registered.
• Normalized $name default from null to '' so the string type is valid without coercion.
• Applied matching typed declarations across all 22 files in connectors/ (e.g. Connector_Settings also types $labels, $permalink_options, and $network_options).
• Updated the inline test double in Connector_Test to use the new typed properties.
• Removed classes/class-connector.php and connectors/ from the Rector skip list now that the family is fully typed; alert and exporter families remain skipped for a follow-up PR.

No behavior changes — this is a static-analysis and type-safety pass only.

Checklist

• Project documentation has been updated to reflect the changes in this pull request, if applicable.
• I have tested the changes in the local development environment (see contributing.md).
• I have added phpunit tests.

Release Changelog

• N/A — internal refactor stacked under XWPENG-47; not targeting master directly.

Release Checklist

• This pull request is to the master branch.
• Release version follows semantic versioning. Does it include breaking changes?
• Update changelog in readme.txt.
• Bump version in stream.php.
• Bump Stable tag in readme.txt.
• Bump version in classes/class-plugin.php.
• Draft a release on GitHub.

Change [ ] to [x] to mark the items as done.