Add BulkSecretsTransformationAttribute for -Secrets parameter normalization

Normalizes Hashtable, OrderedDictionary, PSObject-wrapped, and typed generic dictionaries into IDictionary<string,string>[] before parameter binding, enabling native PowerShell @{...} and [ordered]@{...} literals against the strongly-typed -Secrets parameter on New-/Update-InfisicalSecret. Adds 8 transformation tests; 174/174 passing.

src/PSInfisicalAPI.Tests/BulkSecretConverterTests.cs

@@ -1,4 +1,8 @@
+using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.Management.Automation;
+using PSInfisicalAPI.Cmdlets;
 using PSInfisicalAPI.Errors;
 using PSInfisicalAPI.Secrets;
 using Xunit;
@@ -90,4 +94,116 @@ namespace PSInfisicalAPI.Tests
             Assert.Empty(items);
         }
     }
+
+    public class BulkSecretsTransformationAttributeTests
+    {
+        private static IDictionary<string, string>[] Transform(object input)
+        {
+            BulkSecretsTransformationAttribute attribute = new BulkSecretsTransformationAttribute();
+            object result = attribute.Transform(null, input);
+            return (IDictionary<string, string>[])result;
+        }
+
+        [Fact]
+        public void Transform_Single_Hashtable_Wraps_Into_Array()
+        {
+            Hashtable input = new Hashtable { { "SecretName", "API_KEY" }, { "SecretValue", "abc" } };
+
+            IDictionary<string, string>[] result = Transform(input);
+
+            Assert.Single(result);
+            Assert.Equal("API_KEY", result[0]["SecretName"]);
+            Assert.Equal("abc", result[0]["SecretValue"]);
+        }
+
+        [Fact]
+        public void Transform_Hashtable_Array_Preserves_Order()
+        {
+            Hashtable a = new Hashtable { { "SecretName", "A" }, { "SecretValue", "1" } };
+            Hashtable b = new Hashtable { { "SecretName", "B" }, { "SecretValue", "2" } };
+
+            IDictionary<string, string>[] result = Transform(new object[] { a, b });
+
+            Assert.Equal(2, result.Length);
+            Assert.Equal("A", result[0]["SecretName"]);
+            Assert.Equal("B", result[1]["SecretName"]);
+        }
+
+        [Fact]
+        public void Transform_OrderedDictionary_Converts_To_StringString()
+        {
+            OrderedDictionary input = new OrderedDictionary();
+            input.Add("SecretName", "API_KEY");
+            input.Add("SkipMultilineEncoding", true);
+
+            IDictionary<string, string>[] result = Transform(input);
+
+            Assert.Single(result);
+            Assert.Equal("API_KEY", result[0]["SecretName"]);
+            Assert.Equal("true", result[0]["SkipMultilineEncoding"]);
+        }
+
+        [Fact]
+        public void Transform_Array_Values_Are_Joined_Comma_Separated()
+        {
+            Hashtable input = new Hashtable
+            {
+                { "SecretName", "API_KEY" },
+                { "TagIds", new[] { "tag-1", "tag-2" } }
+            };
+
+            IDictionary<string, string>[] result = Transform(input);
+
+            Assert.Equal("tag-1,tag-2", result[0]["TagIds"]);
+        }
+
+        [Fact]
+        public void Transform_Already_Typed_Array_Passes_Through()
+        {
+            IDictionary<string, string>[] input = new IDictionary<string, string>[]
+            {
+                new Dictionary<string, string> { { "SecretName", "A" }, { "SecretValue", "1" } }
+            };
+
+            IDictionary<string, string>[] result = Transform(input);
+
+            Assert.Same(input, result);
+        }
+
+        [Fact]
+        public void Transform_Null_Input_Returns_Null()
+        {
+            BulkSecretsTransformationAttribute attribute = new BulkSecretsTransformationAttribute();
+            Assert.Null(attribute.Transform(null, null));
+        }
+
+        [Fact]
+        public void Transform_Invalid_Element_Throws_ArgumentTransformationMetadataException()
+        {
+            BulkSecretsTransformationAttribute attribute = new BulkSecretsTransformationAttribute();
+            Assert.Throws<ArgumentTransformationMetadataException>(() =>
+                attribute.Transform(null, new object[] { "not-a-dictionary" }));
+        }
+
+        [Fact]
+        public void Transform_End_To_End_With_Converter_Produces_Bulk_Items()
+        {
+            Hashtable entry = new Hashtable
+            {
+                { "SecretName", "API_KEY" },
+                { "SecretValue", "abc" },
+                { "TagIds", new[] { "tag-1", "tag-2" } },
+                { "SkipMultilineEncoding", true }
+            };
+
+            IDictionary<string, string>[] transformed = Transform(new object[] { entry });
+            InfisicalBulkCreateSecretItem[] items = InfisicalBulkSecretConverter.ToCreateItems(transformed);
+
+            Assert.Single(items);
+            Assert.Equal("API_KEY", items[0].SecretName);
+            Assert.Equal("abc", items[0].SecretValue);
+            Assert.Equal(new[] { "tag-1", "tag-2" }, items[0].TagIds);
+            Assert.True(items[0].SkipMultilineEncoding);
+        }
+    }
 }