Initial commit: Media server and Home Assistant integration

- FastAPI server for Windows media control via WinRT/SMTC
- Home Assistant custom integration with media player entity
- Script button entities for system commands
- Position tracking with grace period for track skip handling
- Server availability detection in HA entity

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

media_server/service/media-server.service

@@ -0,0 +1,36 @@
+[Unit]
+Description=Media Server - REST API for controlling system media playback
+After=network.target sound.target
+Wants=sound.target
+
+[Service]
+Type=simple
+User=%i
+Group=%i
+
+# Environment variables (optional - can also use config file)
+# Environment=MEDIA_SERVER_HOST=0.0.0.0
+# Environment=MEDIA_SERVER_PORT=8765
+# Environment=MEDIA_SERVER_API_TOKEN=your-secret-token
+
+# Working directory
+WorkingDirectory=/opt/media-server
+
+# Start command - adjust path to your Python environment
+ExecStart=/opt/media-server/venv/bin/python -m media_server.main
+
+# Restart policy
+Restart=always
+RestartSec=10
+
+# Security hardening
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=read-only
+PrivateTmp=true
+
+# Required for D-Bus access (MPRIS)
+Environment=DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/%U/bus
+
+[Install]
+WantedBy=multi-user.target