fix: update CPU manufacturer constants to match regenerated SDK

SDK constants were renamed from short form (sdk.AMD) to fully qualified
form (sdk.NodetemplatesV1TemplateConstraintsCPUManufacturerAMD) during
SDK regeneration, causing build failures.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: jozuenoon

castai/resource_node_template.go

@@ -143,7 +143,7 @@ func resourceNodeTemplate() *schema.Resource {
 	supportedArchitectures := []string{ArchAMD64, ArchARM64}
 	supportedOs := []string{OsLinux, OsWindows}
 	supportedSelectorOperations := nodeSelectorOperators
-	supportedCPUManufacturers := []string{string(sdk.AMD), string(sdk.AMPERE), string(sdk.APPLE), string(sdk.AWS), string(sdk.INTEL)}
+	supportedCPUManufacturers := []string{string(sdk.NodetemplatesV1TemplateConstraintsCPUManufacturerAMD), string(sdk.NodetemplatesV1TemplateConstraintsCPUManufacturerAMPERE), string(sdk.NodetemplatesV1TemplateConstraintsCPUManufacturerAPPLE), string(sdk.NodetemplatesV1TemplateConstraintsCPUManufacturerAWS), string(sdk.NodetemplatesV1TemplateConstraintsCPUManufacturerINTEL)}
 
 	return &schema.Resource{
 		CreateContext: resourceNodeTemplateCreate,