chore: initial monorepo scaffold + WDS Phase 1+2 artifacts

- Nx 22.7 monorepo (pnpm 11.1, TypeScript 5.9, Node 24)
- apps/api: NestJS 11 (CJS conforme CODING-RULES.md PGD-DB-004)
- apps/web: React 19 + Vite 8 (ESM)
- libs/shared/api-interface: Zod contract base
- Docker Compose dev: Postgres 18, Valkey 8, MinIO, Mailpit
- WDS artifacts:
  - design-artifacts/A-Product-Brief/ (5 docs canônicos + 16 dialogs)
  - design-artifacts/B-Trigger-Map/ (hub + 4 personas + feature impact)
- Stack canon: STACK.md v2.2 + CODING-RULES.md v2.0 + brand.md
- AGENTS.md + README.md como entrada para devs/agentes

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.agents/skills/bmad-agent-tech-writer/mermaid-gen.md

@@ -0,0 +1,20 @@
+---
+name: mermaid-gen
+description: Create Mermaid-compliant diagrams
+menu-code: MG
+---
+
+# Mermaid Generate
+
+Create a Mermaid diagram based on user description through multi-turn conversation until the complete details are understood.
+
+## Process
+
+1. **Understand the ask** — Clarify what needs to be visualized
+2. **Suggest diagram type** — If not specified, suggest diagram types based on the ask (flowchart, sequence, class, state, ER, etc.)
+3. **Generate** — Create the diagram strictly following Mermaid syntax and CommonMark fenced code block standards
+4. **Iterate** — Refine based on user feedback
+
+## Output
+
+A Mermaid diagram in a fenced code block, ready to render.