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/cis/workflows/design-thinking/workflow.yaml

@@ -1,26 +0,0 @@
-# Design Thinking Workflow Configuration
-name: "design-thinking"
-description: 'Guide human-centered design processes using empathy-driven methodologies. Use when the user says "lets run design thinking" or "I want to apply design thinking"'
-
-# Critical variables load from config_source
-config_source: "{project-root}/_bmad/cis/config.yaml"
-output_folder: "{config_source}:output_folder"
-user_name: "{config_source}:user_name"
-communication_language: "{config_source}:communication_language"
-date: system-generated
-
-# Context can be provided via data attribute when invoking
-# Example: data="{path}/product-context.md" provides project context
-
-# Module path and component files
-installed_path: "{project-root}/_bmad/cis/workflows/design-thinking"
-template: "{installed_path}/template.md"
-instructions: "{installed_path}/instructions.md"
-
-# Required Data Files
-design_methods: "{installed_path}/design-methods.csv"
-
-# Output configuration
-default_output_file: "{output_folder}/design-thinking-{{date}}.md"
-
-standalone: true