feat: architecture refactor — validators, positions, menuUtils, ESLint, tests, CI

Major improvements across the codebase:

- Extract validationUtils.js (548→217 lines) into strategy pattern validators
- Extract menuUtils.js (543→35 lines) into 6 focused menu modules
- Adopt POSITIONS constants across 23 files (183 replacements)
- Eliminate all 71 ESLint warnings (0 errors, 0 warnings)
- Add 158 unit tests for ConfigManager, MeasurementContainer, ValidationUtils
- Add architecture documentation with Mermaid diagrams
- Add CI pipeline (Docker, ESLint, Jest, Makefile)
- Add E2E infrastructure (docker-compose.e2e.yml)

Test results: 377 total (230 Jest + 23 node:test + 124 legacy), all passing
Lint: 0 errors, 0 warnings

Closes #2, #3, #9, #13, #14, #18

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

docker-compose.e2e.yml

@@ -0,0 +1,49 @@
+services:
+  influxdb:
+    image: influxdb:2.7
+    environment:
+      - DOCKER_INFLUXDB_INIT_MODE=setup
+      - DOCKER_INFLUXDB_INIT_USERNAME=admin
+      - DOCKER_INFLUXDB_INIT_PASSWORD=adminpassword
+      - DOCKER_INFLUXDB_INIT_ORG=evolv
+      - DOCKER_INFLUXDB_INIT_BUCKET=evolv
+      - DOCKER_INFLUXDB_INIT_ADMIN_TOKEN=evolv-e2e-token
+    ports:
+      - "8086:8086"
+    healthcheck:
+      test: ["CMD", "influx", "ping"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  nodered:
+    build:
+      context: .
+      dockerfile: Dockerfile.e2e
+    ports:
+      - "1880:1880"
+    depends_on:
+      influxdb:
+        condition: service_healthy
+    environment:
+      - INFLUXDB_URL=http://influxdb:8086
+      - INFLUXDB_TOKEN=evolv-e2e-token
+      - INFLUXDB_ORG=evolv
+      - INFLUXDB_BUCKET=evolv
+    volumes:
+      - ./test/e2e/flows.json:/data/flows.json
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:1880/"]
+      interval: 5s
+      timeout: 5s
+      retries: 10
+
+  grafana:
+    image: grafana/grafana:latest
+    ports:
+      - "3000:3000"
+    environment:
+      - GF_SECURITY_ADMIN_PASSWORD=admin
+      - GF_AUTH_ANONYMOUS_ENABLED=true
+    depends_on:
+      - influxdb