opstate,daemon: list in-flight operations via daemon.operations.list

Prerequisite for `banger update`'s preflight, which refuses to swap
binaries while anything is in flight. Today's opstate.Registry
exposes Insert/Get/Prune but no iteration; without a snapshot
accessor the update flow can't tell whether a vm.create is
mid-prepare-work-disk.

  * opstate.Registry.List(): returns a freshly-allocated snapshot
    of every entry. Mutating the slice doesn't poison the
    registry. Pinned by tests covering the snapshot semantics
    and the empty case.
  * api.OperationSummary / OperationsListResult: a public-shape
    record per op. Today the Kind is always "vm.create" — the
    field exists so future async kinds (image.pull, kernel.pull)
    plug in without an API change.
  * Daemon.ListOperations + daemon.operations.list RPC:
    walks vmService.createOps and emits OperationSummary entries.
    Done ops are included in the snapshot; the update preflight
    filters by Done itself.
  * dispatch_test's documented-methods list updated.

No behaviour change for existing flows; this is a read-only
addition.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/daemon/operations.go

@@ -0,0 +1,37 @@
+package daemon
+
+import (
+	"context"
+
+	"banger/internal/api"
+)
+
+// ListOperations returns a snapshot of every async operation tracked
+// across the daemon's per-kind registries. Today the only kind is
+// vm.create; future async kinds (image build, kernel pull) will plug
+// in here.
+//
+// The primary consumer is `banger update`'s preflight, which refuses
+// to swap binaries while anything is in flight. Done operations are
+// included in the snapshot so an operator running an interactive
+// `banger ... | jq` can see recently-completed work; the update
+// preflight filters by Done itself.
+func (d *Daemon) ListOperations(_ context.Context) (api.OperationsListResult, error) {
+	out := api.OperationsListResult{Operations: []api.OperationSummary{}}
+	if d.vm == nil {
+		return out, nil
+	}
+	for _, op := range d.vm.createOps.List() {
+		snap := op.snapshot()
+		out.Operations = append(out.Operations, api.OperationSummary{
+			ID:        snap.ID,
+			Kind:      "vm.create",
+			Stage:     snap.Stage,
+			Detail:    snap.Detail,
+			Done:      snap.Done,
+			StartedAt: snap.StartedAt,
+			UpdatedAt: snap.UpdatedAt,
+		})
+	}
+	return out, nil
+}