feat(aria): add Svelte SPA frontend and threat events API

- frontend/: full aria.bcos.dev SPA (port 5187) with Dashboard, Threat Events,
  and IOC Management views; Phase 2-3 nav items disabled as placeholders
- ThreatEventController: GET /api/aria/events (paginated, severity/device filter)
  and GET /api/aria/stats (total/critical/high/activeIoc counts)
- Deployed to bcos.dev: hiveiq-aria-frontend container + aria.bcos.dev NPM proxy

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/Dockerfile

@@ -0,0 +1,25 @@
+FROM node:20-alpine AS builder
+
+WORKDIR /build
+
+COPY package*.json ./
+RUN npm ci
+
+COPY . .
+RUN npm run build
+
+FROM node:20-alpine
+
+WORKDIR /app
+
+RUN npm install -g serve
+
+COPY --from=builder /build/dist ./dist
+COPY entrypoint.sh /app/entrypoint.sh
+
+RUN chmod +x /app/entrypoint.sh
+
+EXPOSE 5187
+
+ENTRYPOINT ["/app/entrypoint.sh"]
+CMD ["serve", "-s", "dist", "-l", "5187"]