[TheGreatAxios]

Summary

• Delete the opsh, ast-grep, lexicon, git-rebase, ponytail, idiot-proof, and native-runtime skills. No director attaches any bundled skill, so none of them is loaded by default. ast-grep is dropped for now and will be revisited.
• Remove them from the telemetry allowlist, the plugin manifest description, and the TELEMETRY, PLUGINS, PRODUCT, and ARCHITECTURE docs. The telemetry comment and doc no longer carry hand-maintained skill counts.
• Drop the ast-grep hint from refactor and the opsh and git-rebase mentions from native-integration.

Verification

• bun run check green (7,870 tests).
• No reference to the seven names remains under plugins, src, or docs (outside docs/plans and the CHANGELOG).

Fixes CL-9645

[linear-code]

CL-9645