fix(client): serialize inputSchema as input_schema (#97)

Author: shiqicao

src/commonMain/kotlin/io/modelcontextprotocol/kotlin/sdk/types.kt

@@ -3,6 +3,9 @@
 package io.modelcontextprotocol.kotlin.sdk
 
 import io.modelcontextprotocol.kotlin.sdk.shared.McpJson
+import kotlinx.serialization.EncodeDefault
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonObject
@@ -1043,6 +1046,7 @@ public data class Tool(
     /**
      * A JSON object defining the expected parameters for the tool.
      */
+    @SerialName("input_schema")
     val inputSchema: Input,
 ) {
     @Serializable

src/commonTest/kotlin/ToolSerializationTest.kt

@@ -16,7 +16,7 @@ class ToolSerializationTest {
         {
           "name": "get_weather",
           "description": "Get the current weather in a given location",
-          "inputSchema": {
+          "input_schema": {
             "type": "object",
             "properties": {
               "location": {
@@ -54,4 +54,4 @@ class ToolSerializationTest {
         assertEquals(expected = getWeatherTool, actual = tool)
     }
 
-}
+}