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/opstate/registry.go

@@ -43,6 +43,23 @@ func (r *Registry[T]) Get(id string) (T, bool) {
 	return op, ok
 }
 
+// List returns a snapshot of every operation currently in the
+// registry — both pending and (un-pruned) completed. Callers filter
+// by IsDone() if they care about state. The slice is freshly
+// allocated; mutating it doesn't affect the registry.
+//
+// Used by `banger update`'s preflight to detect in-flight operations
+// before swapping binaries.
+func (r *Registry[T]) List() []T {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	out := make([]T, 0, len(r.byID))
+	for _, op := range r.byID {
+		out = append(out, op)
+	}
+	return out
+}
+
 // Prune drops completed operations last updated before the cutoff.
 func (r *Registry[T]) Prune(before time.Time) {
 	r.mu.Lock()