Automatically close and respond to new issues with:

> Thanks for your report. Please note that this repository is inactive and only kept for legacy purposes.
> 
> If you're reporting a bug or requesting a feature for Processing 4, please open an issue in **[processing/processing4](https://github.com/processing/processing4/issues/new/choose)** instead.`;
> 
> This issue will be closed automatically.

Update workflow to close old issues and PRs

…kflow

Add workflow to redirect issues to Processing 4

> [!NOTE]
> this needs testing against the actual repository.

This PR fixes the following issue: `Error: Unhandled error: HttpError: Unable to create comment because issue is locked.`

See: https://github.com/processing/processing/actions/runs/29001253630

#### Summary of changes:

-   Skips commenting/locking on threads that are already locked (fixes the `HttpError: Unable to create comment because issue is locked` crash)
-   Wraps per-thread processing in try/catch so one failure doesn't abort the whole run
-   Closes PRs via `pulls.update` instead of `issues.update`
-   Adds a `concurrency` group to prevent overlapping runs
-   Handles labels returned as plain strings, not just objects
-   Breaks out of the loop once a thread is newer than the cutoff (list is already sorted) instead of just `continue`
-   Builds close messages via array + `join('\n')` instead of a template literal (avoids leading-whitespace indentation in the posted comment)

…on-locked-issues-1

Fix locked issue crash + robustness changes