acp: Add e2e test support for NativeAgent (#36635)

Release Notes:

- N/A

Cargo.lock

@@ -268,11 +268,14 @@ dependencies = [
  "agent_settings",
  "agentic-coding-protocol",
  "anyhow",
+ "client",
  "collections",
  "context_server",
  "env_logger 0.11.8",
+ "fs",
  "futures 0.3.31",
  "gpui",
+ "gpui_tokio",
  "indoc",
  "itertools 0.14.0",
  "language",
@@ -284,6 +287,7 @@ dependencies = [
  "paths",
  "project",
  "rand 0.8.5",
+ "reqwest_client",
  "schemars",
  "semver",
  "serde",