Work around Sequoia's "Local Network" permission with a helper process (#302)

* Work around Sequoia's "Local Network" permission with a helper process

* README.md: macOS 15 (Sequoia) warning

* Make "orchard dev" unix-specific too, otherwise Release fails

* Fix typo in "localNetworkHerlper"

* Slightly improve the macOS 15 (Sequoia) note

* orchard worker run: better documentation for --user

* Make sure privilege dropping is the first step we do in runWorker()

internal/command/dev/dev.go

@@ -1,3 +1,5 @@
+//go:build unix
+
 package dev
 
 import (

internal/command/dev/dev_unsupported.go

@@ -0,0 +1,9 @@
+//go:build !unix
+
+package dev
+
+import "github.com/spf13/cobra"
+
+func NewCommand() *cobra.Command {
+	return nil
+}