test(hooks): add test coverage for plan-format-validator hook

[Hungdoan565]

Add 11 tests for the plan-format-validator hook covering:

• Valid plan format passes through
• Missing required sections detected
• Malformed markdown handling
• Disabled hook behavior
• Non-plan tool calls skipped

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Summary by cubic

Add 11 tests for the plan-format-validator hook to confirm plan validation works and warnings show only when they should, covering valid plans, malformed task labels (including Final Verification Wave), Edit vs Write tool filtering, non-plan paths, missing files, pre-existing warnings, no checkboxes, and undefined args. Also sync bun.lock platform binaries (oh-my-opencode-*) to 4.5.1.

^{Written for commit 059e3f8. Summary will update on new commits. Review in cubic}