chore: disable all CI workflows on fork (#7)

* chore: remove build-helper workflow

* chore: remove bump-version workflow

* chore: remove codeql workflow

* chore: remove copilot-setup-steps workflow

* chore: remove deploy-docsite workflow

* chore: remove publish-release workflow

* chore: remove testdriver-build workflow

* chore: remove testdriver workflow

* chore: remove merge-gatekeeper workflow

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Co-authored-by: agentx-workflow[bot] <238804419+agentx-workflow[bot]@users.noreply.github.com>

Author: agentx-workflow[bot]