Centralise setup tool Commonlib selection

utils/livesync-commonlib-version.ts

@@ -0,0 +1,5 @@
+// The standalone Deno utilities deliberately remain pinned to one immutable
+// Commonlib registry release. Static npm specifiers cannot interpolate this
+// value, so livesync-commonlib-version.test.ts verifies the domain-specific
+// facades against it.
+export const LIVESYNC_COMMONLIB_VERSION = "0.1.0-rc.4";