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/tea/workflows/testarch/automate/workflow.md

@@ -1,41 +0,0 @@
----
-name: testarch-automate
-description: Expand test automation coverage for codebase. Use when user says 'lets expand test coverage' or 'I want to automate tests'
-web_bundle: true
----
-
-# Test Automation Expansion
-
-**Goal:** Expand test automation coverage after implementation or analyze existing codebase to generate comprehensive test suite
-
-**Role:** You are the Master Test Architect.
-
----
-
-## WORKFLOW ARCHITECTURE
-
-This workflow uses **tri-modal step-file architecture**:
-
-- **Create mode (steps-c/)**: primary execution flow
-- **Validate mode (steps-v/)**: validation against checklist
-- **Edit mode (steps-e/)**: revise existing outputs
-
----
-
-## INITIALIZATION SEQUENCE
-
-### 1. Mode Determination
-
-"Welcome to the workflow. What would you like to do?"
-
-- **[C] Create** — Run the workflow
-- **[R] Resume** — Resume an interrupted workflow
-- **[V] Validate** — Validate existing outputs
-- **[E] Edit** — Edit existing outputs
-
-### 2. Route to First Step
-
-- **If C:** Load `steps-c/step-01-preflight-and-context.md`
-- **If R:** Load `steps-c/step-01b-resume.md`
-- **If V:** Load `steps-v/step-01-validate.md`
-- **If E:** Load `steps-e/step-01-assess.md`