website: Workspace contributor docs streamline

[christian-heusel]

Description of Changes

• chore: Add workspaces as accepted PR prefix
• docs: Unify the current contributor guides

Related Issues

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Checklist

• You have signed off your commits
• Ensure you follow best practices from our contributing guide.
• (for big changes) I will post screenshots of the changes in a PR comment

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[christian-heusel]

cc @HarshPopat23 for a round of review

[HarshPopat23]

Thanks for streamlining the contributor documentation-the consolidation makes sense, and the Task, Feature, and Epic links are preserved.

I noticed two items before LGTM:

1. planning-process.md is deleted, but I could not find an alias or redirect for its existing public URL. Could we redirect /docs/components/workspaces/contributor-guides/planning-process/ to the new contribute/#planning-process section so existing links and bookmarks do not return 404?

2. The title validator now accepts workspaces, and COMMENT_BODY lists it, but the terminal echo "Component value must be..." message still omits workspaces. That message should be updated for consistency.

Apart from these points, the overall direction looks very good.