M7: portfolio polish and final acceptance

Automated migrations on container startup (backend/entrypoint.sh), scripted n8n workflow activation (make n8n-setup), Playwright E2E test covering the full 9-step demo script (verified passing against the live stack, including the previously-unverified 360px responsive layout), evidence screenshots of all main pages, architecture diagram, and artifacts/evidence/final-summary.md with commit/commands/test counts/RAGcore and n8n evidence/MCP sample calls/known limitations/portfolio wording. Verified the complete clean-checkout path from a genuinely wiped-volumes state: automatic migrations, seed, 66 backend tests passing, and a live S1 return round-tripped through a freshly-activated n8n instance. Added .gitattributes to force LF line endings on shell scripts, preventing a real cross-platform breakage of entrypoint.sh's shebang.

Makefile

@@ -1,4 +1,4 @@
-.PHONY: up down logs test seed reset lint
+.PHONY: up down logs test lint seed reset n8n-setup demo e2e
 
 up:
 	docker compose up --build -d
@@ -21,3 +21,19 @@ seed:
 reset:
 	docker compose down -v
 	docker compose up --build -d
+
+# One-time per environment: imports and activates the n8n return-processing workflow.
+# The n8n owner account itself cannot be scripted safely and must be created once at
+# http://localhost:5678/setup (any email/password, no verification required) before
+# this target's activation takes effect. See docs/17-runbook.md.
+n8n-setup:
+	docker compose exec n8n n8n import:workflow --input=//imports/mobilityops-return-processing.json
+	docker compose exec n8n n8n publish:workflow --id=mobilityops-return-processing
+	docker compose restart n8n
+
+# Full deterministic demo bootstrap: build, migrate (automatic on api startup), seed.
+demo: up
+	docker compose exec api python -m app.cli seed --reset
+
+e2e:
+	cd frontend && npx playwright test