S1: Extend protocol.WorkerCapabilities and populate it from the worker… (#14)

ddiff --git a/docs/protocol.md b/docs/protocol.md
iindex 1a38a68..07d7b7c 100644
---- a/docs/protocol.md
++++ b/docs/protocol.md
@@@ -237,8 +237,10 @@ A Node shutting down sends `job_exit` (`stopped`) also for a job acked but not s
  
  `job_cancel` for an id that is not running (unknown, refused or ended) and `job_exit_ack` for an unknown id are
  ignored, with no answer: an `ack` keyed by a job id means the job was accepted.
--A Node that runs jobs lists its classes in `status.capabilities.worker` as `{"runtime_classes": ["function"]}`; the
--key is absent while it runs none, and `worker` is reserved as a plugin name.
++A Node that runs jobs lists its classes and effective local worker caps in `status.capabilities.worker`:
++`{"runtime_classes":["function"],"max_jobs":1,"max_ttl_ms":600000,"max_wall_ms":300000,"max_cpu_ms":300000,"max_mem_bytes":536870912,"max_output_bytes":1048576}`.
++The limits are `worker.caps` with defaults applied; the key is absent while the worker is off, and `worker` is
++reserved as a plugin name.
  
  ### Fault codes
  
ddiff --git a/internal/node/node.go b/internal/node/node.go
iindex 8bd6bc0..c3a2edc 100644
---- a/internal/node/node.go
++++ b/internal/node/node.go
@@@ -815,7 +815,10 @@ func (n *Node) sendStatus() {
  		}
  	}
  	if c := n.jobs.runtimeClasses(); len(c) > 0 {
--		s.Capabilities[protocol.CapWorker] = protocol.WorkerCapabilities{RuntimeClasses: c}
++		caps := n.opt.Config.Worker.Caps.WithDefaults()
++		s.Capabilities[protocol.CapWorker] = protocol.WorkerCapabilities{RuntimeClasses: c, MaxJobs: caps.MaxJobs,
++			MaxTTLMS: caps.MaxTTLMS, MaxWallMS: caps.MaxWallMS, MaxCPUMS: caps.MaxCPUMS,
++			MaxMemBytes: caps.MaxMemBytes, MaxOutputBytes: caps.MaxOutputBytes}
  	}
  	if n.pub != nil {
  		s.Video = n.pub.State()
ddiff --git a/internal/node/worker_test.go b/internal/node/worker_test.go
iindex 86a18e1..8111181 100644
---- a/internal/node/worker_test.go
++++ b/internal/node/worker_test.go
@@@ -10,6 +10,7 @@ import (
  	"log/slog"
  	"os"
  	"path/filepath"
++	"reflect"
  	"slices"
  	"strings"
  	"testing"
@@@ -97,13 +98,22 @@ func startWorkerNode(t *testing.T) *env {
  	e := &env{t: t, srv: srv, node: n, paths: paths, cancel: cancel, done: done}
  	t.Cleanup(e.stop)
  	e.conn = e.nextConn()
--	_, err = e.conn.Expect(protocol.TypeStatus, 10*time.Second, func(m protocol.Message) bool {
++	f, err := e.conn.Expect(protocol.TypeStatus, 10*time.Second, func(m protocol.Message) bool {
  		_, ok := m.(protocol.Status).Capabilities[protocol.CapWorker]
  		return ok
  	})
  	if err != nil {
  		t.Fatal(err)
  	}
++	caps := cfg.Worker.Caps.WithDefaults()
++	want := map[string]any{"runtime_classes": []any{protocol.ClassFunction}, "max_jobs": float64(caps.MaxJobs),
++		"max_ttl_ms": float64(caps.MaxTTLMS), "max_wall_ms": float64(caps.MaxWallMS),
++		"max_cpu_ms": float64(caps.MaxCPUMS), "max_mem_bytes": float64(caps.MaxMemBytes),
++		"max_output_bytes": float64(caps.MaxOutputBytes)}
++	got := f.Msg.(protocol.Status).Capabilities[protocol.CapWorker]
++	if !reflect.DeepEqual(got, want) {
++		t.Fatalf("worker capability = %#v, want %#v", got, want)
++	}
  	return e
  }
  
ddiff --git a/internal/protocol/protocol.go b/internal/protocol/protocol.go
iindex 81ceee5..f148ee4 100644
---- a/internal/protocol/protocol.go
++++ b/internal/protocol/protocol.go
@@@ -393,9 +393,15 @@ type JobExit struct {
  	Usage  JobExitUsage    `json:"usage"`
  }
  
--// WorkerCapabilities is status.capabilities[CapWorker]: the runtime classes this Node runs.
++// WorkerCapabilities is status.capabilities[CapWorker]: the runtime classes this Node runs and its local job caps.
  type WorkerCapabilities struct {
  	RuntimeClasses []string `json:"runtime_classes"`
++	MaxJobs        int      `json:"max_jobs"`
++	MaxTTLMS       int64    `json:"max_ttl_ms"`
++	MaxWallMS      int64    `json:"max_wall_ms"`
++	MaxCPUMS       int64    `json:"max_cpu_ms"`
++	MaxMemBytes    int64    `json:"max_mem_bytes"`
++	MaxOutputBytes int64    `json:"max_output_bytes"`
  }
  
  type DriverStatus struct {