feat: scaffold backend with FastAPI, config files, and health endpoint

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

backend/config/settings.yaml

@@ -0,0 +1,16 @@
+display:
+  resolution: "3840x2160"
+  rotation_interval_seconds: 30
+  transition: "fade"
+  theme: "dark"
+
+odoo:
+  url: "http://localhost:8069"
+  database: "odoo"
+  username: "admin"
+  password: "admin"
+
+refresh:
+  odoo_minutes: 5
+  network_minutes: 10
+  ping_seconds: 60