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/dispatch.go

@@ -50,8 +50,9 @@ func noParamHandler[R any](call func(ctx context.Context, d *Daemon) (R, error))
 // live below the map; they need pre-service validation or raw result
 // encoding that the generic wrapper can't express.
 var rpcHandlers = map[string]handler{
-	"ping":     pingHandler,
-	"shutdown": shutdownHandler,
+	"ping":                 pingHandler,
+	"shutdown":             shutdownHandler,
+	"daemon.operations.list": noParamHandler(daemonOperationsListDispatch),
 
 	"vm.create":        paramHandler(vmCreateDispatch),
 	"vm.create.begin":  paramHandler(vmCreateBeginDispatch),
@@ -214,6 +215,10 @@ func imageCachePruneDispatch(ctx context.Context, d *Daemon, p api.ImageCachePru
 	return d.img.PruneOCICache(ctx, p)
 }
 
+func daemonOperationsListDispatch(ctx context.Context, d *Daemon) (api.OperationsListResult, error) {
+	return d.ListOperations(ctx)
+}
+
 func kernelListDispatch(ctx context.Context, d *Daemon) (api.KernelListResult, error) {
 	return d.img.KernelList(ctx)
 }