st-execute-tasklisted

# st-execute-task Drive the execution of a single task within an existing Strikethroo plan. The skill is assistant-agnostic and self-contained: every script it invokes lives under this skill's `scripts/` directory and is referenced by relative path. ## Critical Rules 1. **Never skip dependency validation** — task execution requires all dependencies to be completed. 2. **Validate task status** — never execute tasks that are already completed, in-progress, or needs-clarification. 3. **Maintain status integrity** — update task status throughout the execution lifecycle. 4. **Document execution** — record all outcomes and issues encountered. 5. **Provide structured output** — always emit the structured result block for orchestrator parsing. ## Inputs The user supplies the numeric plan ID and task ID conversationally. Treat them as the only authoritative source of intent. Do not invent answers to clarifying questions — prompt the user instead. ## Failure Modes - **No strikethroo root found.** Stop and instruct the user to initialize the project. Do not execute the task. - **Plan ID does not resolve.** Stop and surface the script's stderr to the user. Do not guess a different ID. - **Task file not found.** Stop and list available tasks in the plan to help the user identify the correct task ID. - **Task status blocks execution.** If the task is `completed`, `in-progress`, or `needs-clarification`, halt and provide guidance on resolving the blocker. - **Dependency val