refactor: move FetchTransportAdapter to Helpers module for reuse

- Move FetchTransportAdapter from Functions to Sources/Helpers/HTTP/
- Remove duplicate implementation from FunctionsClient
- Keep package visibility for sharing across modules
- Enables reuse for other module migrations in future PRs

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

Co-Authored-By: Claude <[email protected]>

Author: grdsdev

Sources/Functions/FunctionsClient.swift

@@ -11,40 +11,6 @@ import OpenAPIURLSession
 
 let version = Helpers.version
 
-/// A ClientTransport implementation that adapts the old Fetch api.
-struct FetchTransportAdapter: ClientTransport {
-  let fetch: FunctionsClient.FetchHandler
-
-  init(fetch: @escaping FunctionsClient.FetchHandler) {
-    self.fetch = fetch
-  }
-
-  func send(
-    _ request: HTTPTypes.HTTPRequest,
-    body: HTTPBody?,
-    baseURL: URL,
-    operationID: String
-  ) async throws -> (HTTPTypes.HTTPResponse, HTTPBody?) {
-    guard var urlRequest = URLRequest(httpRequest: request) else {
-      throw URLError(.badURL)
-    }
-
-    if let body {
-      urlRequest.httpBody = try await Data(collecting: body, upTo: .max)
-    }
-
-    let (data, response) = try await fetch(urlRequest)
-
-    guard let httpURLResponse = response as? HTTPURLResponse,
-      let httpResponse = httpURLResponse.httpResponse
-    else {
-      throw URLError(.badServerResponse)
-    }
-
-    let body = HTTPBody(data)
-    return (httpResponse, body)
-  }
-}
 
 /// An actor representing a client for invoking functions.
 public final class FunctionsClient: Sendable {

Sources/Helpers/HTTP/FetchTransportAdapter.swift

@@ -0,0 +1,43 @@
+import Foundation
+import HTTPTypes
+import HTTPTypesFoundation
+import OpenAPIRuntime
+
+#if canImport(FoundationNetworking)
+  import FoundationNetworking
+#endif
+
+/// A ClientTransport implementation that adapts the old Fetch api.
+package struct FetchTransportAdapter: ClientTransport {
+  let fetch: @Sendable (_ request: URLRequest) async throws -> (Data, URLResponse)
+
+  package init(fetch: @escaping @Sendable (_ request: URLRequest) async throws -> (Data, URLResponse)) {
+    self.fetch = fetch
+  }
+
+  package func send(
+    _ request: HTTPTypes.HTTPRequest,
+    body: HTTPBody?,
+    baseURL: URL,
+    operationID: String
+  ) async throws -> (HTTPTypes.HTTPResponse, HTTPBody?) {
+    guard var urlRequest = URLRequest(httpRequest: request) else {
+      throw URLError(.badURL)
+    }
+
+    if let body {
+      urlRequest.httpBody = try await Data(collecting: body, upTo: .max)
+    }
+
+    let (data, response) = try await fetch(urlRequest)
+
+    guard let httpURLResponse = response as? HTTPURLResponse,
+      let httpResponse = httpURLResponse.httpResponse
+    else {
+      throw URLError(.badServerResponse)
+    }
+
+    let body = HTTPBody(data)
+    return (httpResponse, body)
+  }
+}