chore: remove BMAD framework files and IDE configuration artifacts

Clean up unused BMAD workflow, agent, and command files across all IDE
configurations (.agent, .clinerules, .cursor, .gemini, .github, .kilocode,
.opencode) and internal module files (_bmad/bmb, _bmad/bmm).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.opencode/skills/bmad-agent-tech-writer/write-document.md

@@ -0,0 +1,20 @@
+---
+name: write-document
+description: Author a document following documentation best practices
+menu-code: WD
+---
+
+# Write Document
+
+Engage in multi-turn conversation until you fully understand the ask. Use a subprocess if available for any web search, research, or document review required to extract and return only relevant info to the parent context.
+
+## Process
+
+1. **Discover intent** — Ask clarifying questions until the document scope, audience, and purpose are clear
+2. **Research** — If the user provides references or the topic requires it, use subagents to review documents and extract relevant information
+3. **Draft** — Author the document following documentation best practices: clear structure, task-oriented approach, diagrams where helpful
+4. **Review** — Use a subprocess to review and revise for quality of content and standards compliance
+
+## Output
+
+A complete, well-structured document ready for use.