Strengthen BugBot release and dependency rules

[willccbb]

Summary

• Add a BugBot rule requiring Verifiers PRs to leave the repo in a releasable state.
• Add a BugBot rule blocking new or modified dependency pins to GitHub sources.
• Include explicit examples for common disallowed dependency forms.
• Update the LICENSE copyright notice to 2026 Prime Intellect.

Testing

• Not run (not requested).

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Note

Low Risk
Low risk: documentation/policy-only changes plus a LICENSE header update, with no runtime code paths affected.

Overview
Updates .cursor/BUGBOT.md to require PRs leave the repo in a releasable state (no hidden failing checks, manual cleanup, or inconsistent release metadata) and to reject dependency pins to GitHub sources, including explicit disallowed examples.

Updates LICENSE copyright to 2026 Prime Intellect.

^{Reviewed by Cursor Bugbot for commit ab5f86e. Bugbot is set up for automated code reviews on this repo. Configure here.}