Update structured-autonomy-plan.prompt.md

Removing extra closing bracket in the model name since it causes error in VS Code

Author: pkarda

prompts/structured-autonomy-plan.prompt.md

@@ -1,7 +1,7 @@
 ---
 name: sa-plan
 description: Structured Autonomy Planning Prompt
-model: Claude Sonnet 4.5 (copilot)]
+model: Claude Sonnet 4.5 (copilot)
 agent: agent
 ---