[client] Make netbird up wait for the daemon to become ready

The CLI up path only tolerated a not-yet-ready daemon via a 10s blocking
dial, so "netbird service start" immediately followed by "netbird up"
(e.g. a container entrypoint) failed with a generic "daemon not running"
error. The container entrypoint worked around this with a shell poll loop
(status --check live) before running up.

Move the readiness wait into the CLI, mirroring how the GUI already dials:

- DialClientGRPCServer now uses grpc.NewClient with a tuned reconnect
  backoff and waits for the connection to reach READY (retrying on
  TRANSIENT_FAILURE) up to a 30s deadline, instead of grpc.DialContext +
  WithBlock with a hard 10s timeout.
- up now polls Status via waitForDaemonStatus, retrying while the RPC is
  Unavailable (socket up but service not yet registered).

Add an explicit daemon-ready signal so clients can wait deterministically
instead of heuristically:

- New optional StatusResponse.daemonReady field (field 5, wire-compatible
  with older GUIs/daemons which leave it unset). Regenerated with the
  pinned protoc v33.1 toolchain so no version churn leaks into the diff.
- The server sets ready once Start succeeds and the DaemonService is
  registered (SetReady, called from the service controller).
- waitForDaemonStatus waits for daemonReady=true (or an already-Connected
  status), with a bounded grace window so older daemons that never set the
  field are not blocked.

Simplify the container entrypoint accordingly: drop the readiness poll
loop (up now waits) and the now-dead NB_ENTRYPOINT_SERVICE_TIMEOUT env,
keeping only the daemon+up process glue and SIGTERM forwarding for clean
shutdown.

client/cmd/dial_test.go

@@ -0,0 +1,176 @@
+package cmd
+
+import (
+	"context"
+	"net"
+	"path/filepath"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/connectivity"
+
+	"github.com/netbirdio/netbird/client/internal"
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+// startUnixGRPCServer starts a bare gRPC server listening on a unix socket at path
+// and returns a stop function. No services are registered; the connectivity-state
+// wait only cares about the transport becoming READY.
+func startUnixGRPCServer(t *testing.T, path string) func() {
+	t.Helper()
+	lis, err := net.Listen("unix", path)
+	if err != nil {
+		t.Fatalf("listen unix %s: %v", path, err)
+	}
+	srv := grpc.NewServer()
+	go func() { _ = srv.Serve(lis) }()
+	return srv.Stop
+}
+
+func TestDialClientGRPCServer_ConnectsWhenServing(t *testing.T) {
+	sock := filepath.Join(t.TempDir(), "nb.sock")
+	stop := startUnixGRPCServer(t, sock)
+	defer stop()
+
+	conn, err := dialClientGRPCServer(context.Background(), "unix://"+sock, 5*time.Second)
+	if err != nil {
+		t.Fatalf("expected connection, got error: %v", err)
+	}
+	defer conn.Close()
+
+	if state := conn.GetState(); state != connectivity.Ready {
+		t.Fatalf("expected READY, got %s", state)
+	}
+}
+
+// TestDialClientGRPCServer_WaitsForLateServer is the core regression test: the
+// daemon socket appears only after the dial has already started, mirroring
+// "netbird service start" immediately followed by "netbird up".
+func TestDialClientGRPCServer_WaitsForLateServer(t *testing.T) {
+	sock := filepath.Join(t.TempDir(), "nb.sock")
+
+	var stop func()
+	timer := time.AfterFunc(1*time.Second, func() {
+		stop = startUnixGRPCServer(t, sock)
+	})
+	defer timer.Stop()
+	defer func() {
+		if stop != nil {
+			stop()
+		}
+	}()
+
+	start := time.Now()
+	conn, err := dialClientGRPCServer(context.Background(), "unix://"+sock, 10*time.Second)
+	if err != nil {
+		t.Fatalf("expected connection after late server start, got error: %v", err)
+	}
+	defer conn.Close()
+
+	if elapsed := time.Since(start); elapsed < 500*time.Millisecond {
+		t.Fatalf("connected too fast (%s); server should not have been up yet", elapsed)
+	}
+	if state := conn.GetState(); state != connectivity.Ready {
+		t.Fatalf("expected READY, got %s", state)
+	}
+}
+
+// fakeStatusServer serves the Status RPC with a programmable response so we can
+// exercise waitForDaemonStatus without spinning up a real engine.
+type fakeStatusServer struct {
+	proto.UnimplementedDaemonServiceServer
+	resp func() *proto.StatusResponse
+}
+
+func (f *fakeStatusServer) Status(context.Context, *proto.StatusRequest) (*proto.StatusResponse, error) {
+	return f.resp(), nil
+}
+
+func startFakeStatusServer(t *testing.T, sock string, resp func() *proto.StatusResponse) func() {
+	t.Helper()
+	lis, err := net.Listen("unix", sock)
+	if err != nil {
+		t.Fatalf("listen unix %s: %v", sock, err)
+	}
+	srv := grpc.NewServer()
+	proto.RegisterDaemonServiceServer(srv, &fakeStatusServer{resp: resp})
+	go func() { _ = srv.Serve(lis) }()
+	return srv.Stop
+}
+
+func dialFake(t *testing.T, sock string) proto.DaemonServiceClient {
+	t.Helper()
+	conn, err := dialClientGRPCServer(context.Background(), "unix://"+sock, 5*time.Second)
+	if err != nil {
+		t.Fatalf("dial fake daemon: %v", err)
+	}
+	t.Cleanup(func() { conn.Close() })
+	return proto.NewDaemonServiceClient(conn)
+}
+
+// New daemon that flips DaemonReady=true after a couple of polls: waitForDaemonStatus
+// must block until the flag is set, then return.
+func TestWaitForDaemonStatus_WaitsForDaemonReady(t *testing.T) {
+	sock := filepath.Join(t.TempDir(), "nb.sock")
+	var polls int32
+	stop := startFakeStatusServer(t, sock, func() *proto.StatusResponse {
+		n := atomic.AddInt32(&polls, 1)
+		return &proto.StatusResponse{
+			Status:      string(internal.StatusConnecting),
+			DaemonReady: n >= 3, // ready only from the 3rd poll on
+		}
+	})
+	defer stop()
+
+	client := dialFake(t, sock)
+	status, err := waitForDaemonStatus(context.Background(), client)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !status.GetDaemonReady() {
+		t.Fatalf("expected DaemonReady=true, got false")
+	}
+	if got := atomic.LoadInt32(&polls); got < 3 {
+		t.Fatalf("expected at least 3 polls before ready, got %d", got)
+	}
+}
+
+// Older daemon that never sets DaemonReady but reports a healthy (Connected)
+// status: waitForDaemonStatus must return promptly via the readiness fallback,
+// not block for the whole grace window.
+func TestWaitForDaemonStatus_OlderDaemonHealthyStatus(t *testing.T) {
+	sock := filepath.Join(t.TempDir(), "nb.sock")
+	stop := startFakeStatusServer(t, sock, func() *proto.StatusResponse {
+		return &proto.StatusResponse{Status: string(internal.StatusConnected)} // DaemonReady unset
+	})
+	defer stop()
+
+	client := dialFake(t, sock)
+	start := time.Now()
+	status, err := waitForDaemonStatus(context.Background(), client)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if status.GetDaemonReady() {
+		t.Fatalf("expected DaemonReady=false from older daemon")
+	}
+	if elapsed := time.Since(start); elapsed > 2*time.Second {
+		t.Fatalf("returned too slowly (%s); healthy status should short-circuit the grace", elapsed)
+	}
+}
+
+func TestDialClientGRPCServer_TimesOutWhenAbsent(t *testing.T) {
+	sock := filepath.Join(t.TempDir(), "never.sock")
+
+	start := time.Now()
+	conn, err := dialClientGRPCServer(context.Background(), "unix://"+sock, 1*time.Second)
+	if err == nil {
+		conn.Close()
+		t.Fatal("expected timeout error, got nil")
+	}
+	if elapsed := time.Since(start); elapsed < 900*time.Millisecond {
+		t.Fatalf("returned too early (%s); should have waited ~timeout", elapsed)
+	}
+}