feat: guardian as an extension (contributors part) (#22216)

Part 1 of guardian as extension. This bind all the logic to spawn
another agent from an extension and it adds `ThreadId` in the start
thread collaborator

codex-rs/Cargo.lock

@@ -1904,6 +1904,7 @@ dependencies = [
  "codex-file-watcher",
  "codex-git-attribution",
  "codex-git-utils",
+ "codex-guardian",
  "codex-hooks",
  "codex-login",
  "codex-mcp",
@@ -2906,6 +2907,7 @@ dependencies = [
  "codex-core",
  "codex-extension-api",
  "codex-features",
+ "codex-protocol",
  "pretty_assertions",
 ]
 
@@ -2933,6 +2935,15 @@ dependencies = [
  "walkdir",
 ]
 
+[[package]]
+name = "codex-guardian"
+version = "0.0.0"
+dependencies = [
+ "codex-core",
+ "codex-extension-api",
+ "codex-protocol",
+]
+
 [[package]]
 name = "codex-hooks"
 version = "0.0.0"