feat(pi): update to the latest stable release by default

tools/tht/cmd/tht/main.go

@@ -54,8 +54,10 @@ Commands:
                       Select closed backend defaults interactively on a TTY; all flags are required otherwise.
   pi restart --yes [--drain]
                       Recreate only core with the currently selected Pi image and verify readiness.
+  pi update [--version V]
+                      Rebuild the latest stable Pi release, or an explicit version, and recreate only core.
   pi update --version V --source build --yes [--drain]
-                      Rebuild a pinned Pi version and recreate only core.
+                      Advanced explicit build form retained for compatibility.
   pi update --version V --source pull --image IMAGE@sha256:DIGEST --yes [--drain]
                       Pull an immutable candidate and recreate only core.
   pi rollback --yes   Restore the image recorded by the latest Pi update.
@@ -75,6 +77,11 @@ Commands:
   workspace preprocess run --workspace ID [--resume RUN] [--json]
 `
 
+var (
+	newPiRegistryClient      = pi.NewNPMRegistryClient
+	readPiRuntimePackageName = pi.ReadRuntimePackageName
+)
+
 func main() {
 	os.Exit(run(context.Background(), os.Args[1:], os.Stdout, os.Stderr))
 }
@@ -487,12 +494,21 @@ func piCommand(ctx context.Context, installation config.Installation, runner com
 		if err != nil {
 			return commandUsageError(stderr, err.Error())
 		}
-		result, err := pi.Update(ctx, controlled, request)
+		var registry pi.RegistryClient
+		packageName := ""
+		if request.Version == "" {
+			packageName, err = readPiRuntimePackageName(installation.ProjectDirectory)
+			if err != nil {
+				return commandUsageError(stderr, "pi update latest-version lookup is unavailable: "+err.Error())
+			}
+			registry = newPiRegistryClient()
+		}
+		result, err := pi.UpdateWithResolvedVersion(ctx, controlled, request, packageName, registry)
 		if err != nil {
 			return piFailure(stderr, err, secretValues)
 		}
 		if result.Phase == pi.PhaseNoop {
-			fmt.Fprintf(stdout, "Pi already runs requested version %s; no container was recreated.\n", request.Version)
+			fmt.Fprintf(stdout, "Pi already runs requested version %s; no container was recreated.\n", result.Version)
 			return 0
 		}
 		fmt.Fprintf(stdout, "Pi update verified. Recovery metadata: %s\n", result.StatePath)
@@ -647,6 +663,7 @@ func parsePiConfigureArgs(args []string) (pi.Defaults, error) {
 
 func parsePiUpdateArgs(args []string, statePath, restartStatePath string) (pi.Request, error) {
 	request := pi.Request{StatePath: statePath, RestartStatePath: restartStatePath}
+	sourceSpecified := false
 	for len(args) > 0 {
 		switch args[0] {
 		case "--version":
@@ -659,6 +676,7 @@ func parsePiUpdateArgs(args []string, statePath, restartStatePath string) (pi.Re
 				return pi.Request{}, errors.New("--source requires build or pull")
 			}
 			request.Source, args = pi.Source(args[1]), args[2:]
+			sourceSpecified = true
 		case "--image":
 			if len(args) < 2 || request.Image != "" {
 				return pi.Request{}, errors.New("--image requires one digest-pinned image reference")
@@ -678,11 +696,17 @@ func parsePiUpdateArgs(args []string, statePath, restartStatePath string) (pi.Re
 			return pi.Request{}, fmt.Errorf("unknown pi update option %q", args[0])
 		}
 	}
-	if request.Version == "" {
-		return pi.Request{}, errors.New("pi update requires --version <pinned-version>")
+	if !sourceSpecified {
+		if request.Image != "" {
+			return pi.Request{}, errors.New("--image is valid only with --source pull")
+		}
+		request.Source = pi.BuildSource
+		request.Confirm = true
+		request.Drain = true
+		return request, nil
 	}
-	if request.Source == "" {
-		return pi.Request{}, errors.New("pi update requires explicit --source build or pull")
+	if request.Version == "" {
+		return pi.Request{}, errors.New("pi update with --source requires --version <pinned-version>")
 	}
 	if request.Source != pi.BuildSource && request.Source != pi.PullSource {
 		return pi.Request{}, errors.New("--source requires build or pull")