feat: initial Speedboard implementation

sitespeed.io web UI with Express/Pug/SQLite — port 3132.
Includes job queue, SSE live log, full metrics dashboard,
site history, CO2/axe/CWV sections, and Docker support.

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

docker-compose.yml

@@ -0,0 +1,28 @@
+version: '3.9'
+
+services:
+  speedboard:
+    build: .
+    image: speedboard:latest
+    container_name: speedboard
+    restart: unless-stopped
+    ports:
+      - "3132:3132"
+    volumes:
+      # Persist reports and SQLite database outside the container
+      - speedboard-reports:/data/reports
+      - speedboard-db:/data/db
+    environment:
+      PORT: "3132"
+      IN_DOCKER: "1"
+      # Store SQLite DB on the persistent volume
+      DB_PATH: /data/db/speedboard.db
+    # sitespeed.io needs /dev/shm for Chrome
+    shm_size: '2gb'
+    # Allow Chrome --no-sandbox
+    security_opt:
+      - seccomp:unconfined
+
+volumes:
+  speedboard-reports:
+  speedboard-db: