feat(F-001): scaffold modular monolith skeleton with boundary checker

- TypeScript + Fastify skeleton under project/ (src/modules, shared, infrastructure, app)
- scripts/check-module-boundaries.mjs enforcing module public-API rules (tested with fixtures)
- GET /health endpoint, error envelope without stack leakage
- specs/F-001-scaffold (SPEC/DESIGN/TASKS/TESTS), spec/tech.md dependency justification
- 30-ticket MercadoDeVida roadmap in backlog/features.json, spec/roadmap.md
- All gates approved: reviewer, security, qa; verify.sh green

work/artifacts/F-001/documenter.md

@@ -0,0 +1,22 @@
+# Documenter — F-001 Scaffold modular monolith skeleton
+
+done -> work/artifacts/F-001/documenter.md
+
+## Why documentation applies
+F-001 introduces new developer-facing contracts: npm scripts, module boundary rules, and project layout.
+
+## Documents reviewed/produced
+- `project/README.md` (created at build stage, verified accurate):
+  - requirements (Node >= 22, npm)
+  - all 6 npm scripts match package.json exactly: build, start, lint, lint:boundaries, typecheck, test
+  - layout diagram matches actual tree
+  - module rules match scripts/check-module-boundaries.mjs behavior (R1/R2)
+- `specs/F-001-scaffold/` SPEC/DESIGN/TASKS/TESTS kept consistent with final implementation (TESTS.md updated at build stage).
+- `spec/tech.md` completed with stack and dependency justification table (security policy requirement).
+
+## Verification
+- `grep` cross-check: README command list == package.json scripts keys (build, start, lint, lint:boundaries, typecheck, test) -> match.
+- No API docs needed yet beyond /health (documented in implementer.md and SPEC.md).
+
+## Pending docs (not this ticket)
+- API reference will start being meaningful from F-005 onward.