feat: bake BF Node-RED nodes into nodered Docker image

- New deploy/docker/Dockerfile.nodered extends nodered/node-red,
  npm-installs the workspace nodered/ package into
  /usr/src/node-red/node_modules so bf-* nodes auto-load on boot.
- docker-compose nodered service switched from public image to
  this build context. Rebuilding (--build) picks up node changes.

deploy/docker/Dockerfile.nodered

@@ -0,0 +1,21 @@
+# BetterFrame Node-RED image with bundled BF nodes preinstalled.
+#
+# Extends official nodered/node-red, installs the workspace nodered/
+# package into Node-RED's module tree. Rebuilding the image
+# (docker compose up --build) picks up any node changes.
+
+FROM nodered/node-red:latest
+
+USER root
+
+# Copy our nodes into a build dir
+COPY nodered /tmp/betterframe-nodes
+
+# Install into Node-RED's own node_modules so they're found at runtime.
+# Survives /data volume mounts because /usr/src/node-red is image-level.
+RUN cd /usr/src/node-red && \
+    npm install --omit=dev /tmp/betterframe-nodes && \
+    rm -rf /tmp/betterframe-nodes && \
+    chown -R node-red:root /usr/src/node-red/node_modules
+
+USER node-red

deploy/docker/docker-compose.yml

@@ -44,7 +44,9 @@ services:
       - betterframe
 
   nodered:
-    image: nodered/node-red:latest
+    build:
+      context: ../..
+      dockerfile: deploy/docker/Dockerfile.nodered
     container_name: betterframe-nodered
     restart: unless-stopped
     environment: