feat(assets): wire builder into dispatch, shim, smoke, docs

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/dispatch/dispatch_test.go

@@ -151,6 +151,7 @@ func TestBuilderHelpIsOK(t *testing.T) {
 func TestCanonicalCommandSurface(t *testing.T) {
 	want := map[string][]string{
 		"depot":   {"status", "push", "verify", "get", "pull"},
+		"assets":  {"compile", "convert", "upscale", "check-mdl", "fix-mdl", "check-dupes", "clean-dupes"},
 		"hak":     {"build", "manifest"},
 		"module":  {"build", "extract", "validate", "compare", "manifest"},
 		"topdata": {"validate", "build", "package", "compare", "convert"},
@@ -172,10 +173,10 @@ func TestRegistryCommandNamesAndAliasesAreUnambiguous(t *testing.T) {
 	for _, builder := range Registry {
 		seen := map[string]bool{}
 		for _, command := range builder.Commands {
-			// depot parses its own subcommands and bypasses AppCommand routing
-			// entirely (see the depot special-case in runBuilder), so its
-			// Commands carry no AppCommand.
-			requireAppCommand := builder.Name != "depot"
+			// depot and assets parse their own subcommands and bypass AppCommand
+			// routing entirely (see the self-contained-builder branch in
+			// runBuilder), so their Commands carry no AppCommand.
+			requireAppCommand := builder.Name != "depot" && builder.Name != "assets"
 			if command.Name == "" || command.Summary == "" || command.Usage == "" || (requireAppCommand && command.AppCommand == "") {
 				t.Errorf("%s has incomplete command metadata: %#v", builder.Name, command)
 			}