app-server-test-client websocket client and thread tools (#11755)

- add websocket endpoint mode with default ws://127.0.0.1:4222 while
keeping stdio codex-bin path compatibility
- add thread-resume (follow stream) and thread-list commands for manual
thread lifecycle testing
- quickstart docs

codex-rs/app-server-test-client/Cargo.toml

@@ -14,4 +14,6 @@ codex-app-server-protocol = { workspace = true }
 codex-protocol = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
+tungstenite = { workspace = true }
+url = { workspace = true }
 uuid = { workspace = true, features = ["v4"] }