Add support for structured dtypes to zarr3 driver, open structs as void

tensorstore/driver/zarr3/BUILD

@@ -96,8 +96,8 @@ tensorstore_cc_library(
 
 tensorstore_cc_library(
     name = "metadata",
-    srcs = ["metadata.cc"],
-    hdrs = ["metadata.h"],
+    srcs = ["metadata.cc", "dtype.cc"],
+    hdrs = ["metadata.h", "dtype.h"],
     deps = [
         ":default_nan",
         ":name_configuration_json_binder",
@@ -146,6 +146,23 @@ tensorstore_cc_library(
     ],
 )
 
+tensorstore_cc_test(
+    name = "dtype_test",
+    size = "small",
+    srcs = ["dtype_test.cc"],
+    deps = [
+        ":metadata",
+        "//tensorstore:data_type",
+        "//tensorstore:index",
+        "//tensorstore/internal/testing:json_gtest",
+        "//tensorstore/util:status_testutil",
+        "@abseil-cpp//absl/status",
+        "@abseil-cpp//absl/strings",
+        "@googletest//:gtest_main",
+        "@nlohmann_json//:json",
+    ],
+)
+
 tensorstore_cc_test(
     name = "driver_test",
     size = "small",
@@ -203,10 +220,12 @@ tensorstore_cc_library(
     srcs = ["chunk_cache.cc"],
     hdrs = ["chunk_cache.h"],
     deps = [
+        ":metadata",
         "//tensorstore:array",
         "//tensorstore:array_storage_statistics",
         "//tensorstore:batch",
         "//tensorstore:box",
+        "//tensorstore:contiguous_layout",
         "//tensorstore:index",
         "//tensorstore:index_interval",
         "//tensorstore:rank",
@@ -223,6 +242,7 @@ tensorstore_cc_library(
         "//tensorstore/internal:intrusive_ptr",
         "//tensorstore/internal:lexicographical_grid_index_key",
         "//tensorstore/internal:regular_grid",
+        "//tensorstore:strided_layout",
         "//tensorstore/internal:storage_statistics",
         "//tensorstore/internal/cache",
         "//tensorstore/internal/cache:chunk_cache",