Start the Go rewrite: jsjson, awg-ctrl port, differential bench

- internal/jsjson: JSON.stringify-compatible encoder and order-preserving decoder,
  tested against fixtures produced by Node itself
- internal/ctrl: awg-ctrl in Go (params, vpn:// keys, users, peers, sync, 3.1
  upgrade, CAKE shaping, metrics, monitor job, Express-compatible HTTP layer)
- internal/iauth, internal/logx: internal Ed25519 tokens and logging
- tools/diffbench: Docker bench with stubbed awg/ip/tc/nft that runs one scenario
  against the TS and Go implementations for comparison

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/jsjson/jsjson_test.go

@@ -0,0 +1,84 @@
+package jsjson
+
+import (
+	"encoding/json"
+	"os"
+	"testing"
+)
+
+type fixture struct {
+	Strings []struct{ In, Out string } `json:"strings"`
+	Numbers []struct {
+		In  json.RawMessage `json:"in"`
+		Out string          `json:"out"`
+		Str string          `json:"str"`
+	} `json:"numbers"`
+	Objects []struct {
+		In      json.RawMessage `json:"in"`
+		Compact string          `json:"compact"`
+		Indent2 string          `json:"indent2"`
+	} `json:"objects"`
+}
+
+// Эталон — вывод JSON.stringify самого Node (tools/golden/jsjson.mjs).
+func TestAgainstNode(t *testing.T) {
+	raw, err := os.ReadFile("../../testdata/golden/jsjson.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var f fixture
+	if err := json.Unmarshal(raw, &f); err != nil {
+		t.Fatal(err)
+	}
+	for _, c := range f.Strings {
+		if got := string(MustMarshal(c.In)); got != c.Out {
+			t.Errorf("string %q: got %s want %s", c.In, got, c.Out)
+		}
+	}
+	for _, c := range f.Numbers {
+		v, err := Decode(c.In)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if s, ok := v.(string); ok { // NaN / Infinity переданы строкой
+			_ = s
+			continue
+		}
+		x := v.(float64)
+		if got := Number(x); got != c.Str {
+			t.Errorf("String(%s): got %s want %s", c.In, got, c.Str)
+		}
+		if got := string(MustMarshal(x)); got != c.Out {
+			t.Errorf("JSON.stringify(%s): got %s want %s", c.In, got, c.Out)
+		}
+	}
+	for _, c := range f.Objects {
+		v, err := Decode(c.In)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got := string(MustMarshal(v)); got != c.Compact {
+			t.Errorf("compact:\n got %s\nwant %s", got, c.Compact)
+		}
+		got, _ := MarshalIndent(v, "  ")
+		if string(got) != c.Indent2 {
+			t.Errorf("indent:\n got %s\nwant %s", got, c.Indent2)
+		}
+	}
+}
+
+func TestStructOrderAndOmit(t *testing.T) {
+	type S struct {
+		B    string `json:"b"`
+		A    int    `json:"a"`
+		Opt  string `json:"opt,omitempty"`
+		Skip string `json:"-"`
+	}
+	if got := string(MustMarshal(S{B: "x", A: 1})); got != `{"b":"x","a":1}` {
+		t.Fatal(got)
+	}
+	o := Object{{"x", 1}, {"gone", Undefined}, {"y", []string(nil)}}
+	if got := string(MustMarshal(o)); got != `{"x":1,"y":[]}` {
+		t.Fatal(got)
+	}
+}