Add the shared packages for the sharks stack

model, tunnel, wg, authtoken, netguard, docker and dotenv, split out of the
original single repository so Hammerhead, Blacktip and Bamboo can live in
their own repos and import them. README extended; LICENSE unchanged.

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

docker/docker_test.go

@@ -0,0 +1,48 @@
+package docker
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestListParsesContainers(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/containers/json" {
+			http.NotFound(w, r)
+			return
+		}
+		w.Write([]byte(`[
+		 {"Id":"abcdef1234567890","Names":["/minecraft"],"Image":"itzg/minecraft-server","State":"running",
+		  "Ports":[{"PrivatePort":25565,"PublicPort":25565,"Type":"tcp"},{"PrivatePort":25565,"PublicPort":25565,"Type":"tcp"},{"PrivatePort":8123,"Type":"tcp"}],
+		  "NetworkSettings":{"Networks":{"bridge":{"IPAddress":"172.17.0.2"},"none":{"IPAddress":""}}}},
+		 {"Id":"1111","Names":["/db"],"Image":"postgres","State":"running","Ports":[],"NetworkSettings":{"Networks":{}}}
+		]`))
+	}))
+	defer srv.Close()
+	t.Setenv("DOCKER_HOST", "tcp://"+strings.TrimPrefix(srv.URL, "http://"))
+
+	got, err := List(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(got) != 2 || got[0].Name != "db" || got[1].Name != "minecraft" {
+		t.Fatalf("unexpected list: %+v", got)
+	}
+	mc := got[1]
+	if mc.ID != "abcdef123456" || len(mc.Ports) != 2 || mc.Ports[0].Public != 25565 || mc.Ports[1].Public != 0 {
+		t.Errorf("ports/id wrong: %+v", mc)
+	}
+	if mc.Networks["bridge"] != "172.17.0.2" || len(mc.Networks) != 1 {
+		t.Errorf("networks wrong: %+v", mc.Networks)
+	}
+}
+
+func TestListUnreachable(t *testing.T) {
+	t.Setenv("DOCKER_HOST", "tcp://127.0.0.1:1")
+	if _, err := List(context.Background()); err == nil {
+		t.Fatal("expected an error when docker is not running")
+	}
+}