refactor(sidecarassets): rename internal/sidecar to internal/sidecarassets

internal/sidecarassets/embed_real.go

@@ -0,0 +1,12 @@
+//go:build withsidecar
+
+package sidecarassets
+
+import _ "embed"
+
+//go:embed assets/sidecar-all.jar
+var embeddedJAR []byte
+
+// IsPlaceholder reports whether the binary was built without the real
+// sidecar JAR embedded. -tags withsidecar builds always return false.
+func IsPlaceholder() bool { return false }