This skill should be used when the user says "implementing", "arness implementing", "start implementing", "execute the plan", "build it", "implement this", "run the tasks", "execute", "start building", "implement the feature", "implement the fix", "quick change", "swift", "swift mode", "quick implementation", "standard", "standard mode", "standard implementation", "start execution", "build the feature", "arn-implementing", or wants to execute an implementation plan, run a quick implementation, a standard-tier implementation, or manage the build-simplify-review cycle. Chains to arn-shipping at completion.