feat: add macOS build, Docker image, and CI workflows

macOS (.dmg):
- Add mac build config to apps/desktop/package.json (x64 + arm64 DMGs)
- .github/workflows/build-mac.yml — builds on macos-latest, uploads to release

Docker (headless scheduler + web remote):
- docker/server.js — Node.js entry point using homebridge-plugin lib;
  REST API + WebSocket, serves mobile web UI on PORT (default 3456)
- docker/package.json — production deps (adm-zip, axios, sql.js, ws, xml2js, xmlbuilder2)
- Dockerfile — node:20-alpine image; VOLUME /data for persistent config
- .github/workflows/build-docker.yml — builds linux/amd64+arm64,
  pushes to ghcr.io/k0rb3nd4ll4s/dibby-wemo-manager

Usage:
  docker run -d --network host -v /opt/wemo:/data \
    ghcr.io/k0rb3nd4ll4s/dibby-wemo-manager:latest

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

apps/desktop/package.json

@@ -45,6 +45,16 @@
     "directories": {
       "output": "dist"
     },
+    "mac": {
+      "target": [
+        { "target": "dmg", "arch": ["x64", "arm64"] }
+      ],
+      "icon": "resources/icon.png",
+      "category": "public.app-category.utilities"
+    },
+    "dmg": {
+      "title": "Dibby Wemo Manager"
+    },
     "win": {
       "target": [
         {