chore: upgrade BMAD framework to skill-based architecture

Migrates from slash-command files (.claude/commands, .cursor/commands)
to the new skill-based architecture with workflow step files.

_bmad/bmm/workflows/4-implementation/sprint-status/workflow.yaml

@@ -1,25 +0,0 @@
-# Sprint Status - Implementation Tracker
-name: sprint-status
-description: 'Summarize sprint status and surface risks. Use when the user says "check sprint status" or "show sprint status"'
-author: "BMad"
-
-# Critical variables from config
-config_source: "{project-root}/_bmad/bmm/config.yaml"
-user_name: "{config_source}:user_name"
-communication_language: "{config_source}:communication_language"
-document_output_language: "{config_source}:document_output_language"
-implementation_artifacts: "{config_source}:implementation_artifacts"
-
-# Workflow components
-installed_path: "{project-root}/_bmad/bmm/workflows/4-implementation/sprint-status"
-instructions: "{installed_path}/instructions.md"
-
-# Inputs
-sprint_status_file: "{implementation_artifacts}/sprint-status.yaml"
-
-# Smart input file references
-input_file_patterns:
-  sprint_status:
-    description: "Sprint status file generated by sprint-planning"
-    whole: "{implementation_artifacts}/sprint-status.yaml"
-    load_strategy: "FULL_LOAD"