Address review: Range(Type,string,string) for long, add SDK using to Rpc

Use Range(typeof(long), ...) overload since RangeAttribute has no
long constructor. Add 'using GitHub.Copilot.SDK' to Rpc.cs header
so MillisecondsTimeSpanConverter resolves when duration fields exist.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: stephentoub

dotnet/src/Generated/Rpc.cs

@@ -220,17 +220,24 @@ function emitDataAnnotations(schema: JSONSchema7, indent: string): string[] {
         attrs.push(`${indent}[Base64String]`);
     }
 
-    // [Range]for minimum/maximum
+    // [Range] for minimum/maximum
     const hasMin = typeof schema.minimum === "number";
     const hasMax = typeof schema.maximum === "number";
     if (hasMin || hasMax) {
-        const min = hasMin ? String(schema.minimum) : (schema.type === "integer" ? "long.MinValue" : "double.MinValue");
-        const max = hasMax ? String(schema.maximum) : (schema.type === "integer" ? "long.MaxValue" : "double.MaxValue");
         const namedArgs: string[] = [];
         if (schema.exclusiveMinimum === true) namedArgs.push("MinimumIsExclusive = true");
         if (schema.exclusiveMaximum === true) namedArgs.push("MaximumIsExclusive = true");
         const namedSuffix = namedArgs.length > 0 ? `, ${namedArgs.join(", ")}` : "";
-        attrs.push(`${indent}[Range(${min}, ${max}${namedSuffix})]`);
+        if (schema.type === "integer") {
+            // Use Range(Type, string, string) overload since RangeAttribute has no long constructor
+            const min = hasMin ? String(schema.minimum) : "long.MinValue";
+            const max = hasMax ? String(schema.maximum) : "long.MaxValue";
+            attrs.push(`${indent}[Range(typeof(long), "${min}", "${max}"${namedSuffix})]`);
+        } else {
+            const min = hasMin ? String(schema.minimum) : "double.MinValue";
+            const max = hasMax ? String(schema.maximum) : "double.MaxValue";
+            attrs.push(`${indent}[Range(${min}, ${max}${namedSuffix})]`);
+        }
     }
 
     // [RegularExpression] for pattern
@@ -1190,6 +1197,7 @@ using System.ComponentModel.DataAnnotations;
 using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
 using System.Text.Json.Serialization;
+using GitHub.Copilot.SDK;
 using StreamJsonRpc;
 
 namespace GitHub.Copilot.SDK.Rpc;