fix(cli): remove triple blank lines and redundant inline import in plan.py

Remove two triple blank lines (PEP 8 violation) between function
definitions in plan.py that were causing the CI lint gate to fail.
Also remove a redundant inline import of LifecyclePlan inside
_execute_output_dict() since it is already imported at module level.

ISSUES CLOSED: #9450

src/cleveragents/cli/commands/plan.py

@@ -347,8 +347,6 @@ def _execute_output_dict(
     Returns:
         A JSON-serialisable dict matching the spec-required envelope.
     """
-    from cleveragents.domain.models.core.plan import Plan as LifecyclePlan
-
     if not isinstance(plan, LifecyclePlan):
         # Legacy plan fallback — return minimal envelope
         return {
@@ -479,7 +477,6 @@ def _execute_output_dict(
 
 
 
-
 def _get_progress_status(phase: PlanPhase, state: ProcessingState) -> str:
     """Determine progress status based on plan phase and state.