Add read-only web UI

Serves Pete's classified-story archive over HTTP alongside the Matrix
bot. Three sections (gaming/tech/politics), Animal-Crossing-vibe Tailwind
templates, day/night palette driven by the visitor's browser clock.
Web port configurable via web.listen_addr and ${PETE_WEB_PORT} in
docker-compose. Tailwind built in a node stage in the Dockerfile so
deployments don't need node at runtime.

docker-compose.yml

@@ -4,6 +4,8 @@ services:
     restart: unless-stopped
     environment:
       - MATRIX_ACCESS_TOKEN=${MATRIX_ACCESS_TOKEN}
+    ports:
+      - "${PETE_WEB_PORT:-8080}:8080"
     volumes:
       - ./data:/app/data
       - ./config.yaml:/app/config.yaml:ro