Switch remote deploy to vendored source builds

Move remote deployment to a vendored source bundle built on the target host via Docker so redeploys no longer require local cross-compilation or host Go installation.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

vendor/github.com/godbus/dbus/v5/homedir.go

@@ -0,0 +1,25 @@
+package dbus
+
+import (
+	"os"
+	"os/user"
+)
+
+// Get returns the home directory of the current user, which is usually the
+// value of HOME environment variable. In case it is not set or empty, os/user
+// package is used.
+//
+// If linking statically with cgo enabled against glibc, make sure the
+// osusergo build tag is used.
+//
+// If needing to do nss lookups, do not disable cgo or set osusergo.
+func getHomeDir() string {
+	homeDir := os.Getenv("HOME")
+	if homeDir != "" {
+		return homeDir
+	}
+	if u, err := user.Current(); err == nil {
+		return u.HomeDir
+	}
+	return "/"
+}