v0.1.0-alpha: interactive demo platform core

- Fastify API: demos/steps CRUD, content-addressed assets, scoped API keys
  (read/author/publish/admin, draft-only default per D4)
- Player: image + sandboxed DOM steps, hotspots, tooltips, keyboard nav,
  privacy-first beacons (no IP storage, viewer tokens only — R7)
- Editor: React SPA — demo list, drag-to-draw hotspots, annotations, publish
- MCP server: Streamable HTTP, scope-filtered tools, untrusted-data wrapping
  on viewer-supplied content (R8); platform never calls a model
- Capture extension (MV3): screenshot-flow recording, hotspots pre-placed
  from real clicks
- Docker: single app image + postgres, Traefik-ready (expose only)

E2E verified: capture->author->publish->play->beacon->lead->analytics + full
MCP tool surface with scope filtering.

docker-compose.yml

@@ -0,0 +1,33 @@
+services:
+  app:
+    build: .
+    restart: unless-stopped
+    expose:
+      - "3000"
+    environment:
+      - DATABASE_URL=postgresql://demoplatform:${DB_PASSWORD:-demoplatform}@db:5432/demoplatform
+      - DATA_DIR=/data
+    volumes:
+      - app-data:/data
+    depends_on:
+      db:
+        condition: service_healthy
+
+  db:
+    image: postgres:17-alpine
+    restart: unless-stopped
+    environment:
+      - POSTGRES_USER=demoplatform
+      - POSTGRES_PASSWORD=${DB_PASSWORD:-demoplatform}
+      - POSTGRES_DB=demoplatform
+    volumes:
+      - db-data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U demoplatform"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+volumes:
+  app-data:
+  db-data: