feat(server): add tool name validation per SEP-986 (#695)

Add warn-only validation for tool names at registration time, following
the MCP tool naming standard (SEP-986)

closes #417 

## How Has This Been Tested?
unit tests 

## Breaking Changes
none

## Types of changes
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed

integration-test/src/jvmTest/kotlin/io/modelcontextprotocol/kotlin/sdk/server/ServerToolsTest.kt

@@ -98,6 +98,16 @@ class ServerToolsTest : AbstractServerFeaturesTest() {
         assertFalse(toolListChangedNotificationReceived, "No notification should be sent when tool doesn't exist")
     }
 
+    @Test
+    fun `addTool should succeed with non-conforming tool name`() = runTest {
+        server.addTool("my invalid tool!", "Tool with non-conforming name", ToolSchema()) {
+            CallToolResult(listOf(TextContent("It works")))
+        }
+
+        val result = server.removeTool("my invalid tool!")
+        assertTrue(result, "Tool with non-conforming name should have been registered and removable")
+    }
+
     @Test
     fun `removeTool should throw when tools capability is not supported`() = runTest {
         var toolListChangedNotificationReceived = false