Dev server updates (#52)

* Start dev server on any port

* Move dev DB into project folder

* Choose free ports for dev server

* Reliability

* Both processes get env vars

* And open browser

.gitignore

@@ -74,4 +74,7 @@ backend/bindings
 build-npm-package-codesign.sh
 
 npx-cli/dist
-db.sqlite
+backend/db.sqlite
+
+# Development ports file
+.dev-ports.json