shadow: type muxer/discovery as Literal

Constrain muxer/discovery to their valid values with Literal instead of plain
str, matching how nimlibp2p.py types them.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: radiken

src/deployments/experiments/libp2p/shadow_gossipsub.py

@@ -1,7 +1,7 @@
 # Shadow GossipSub experiment: N nim libp2p peers + 1 publisher inside Shadow on a
 # single k8s pod. See the "Using Shadow at DST" runbook in Notion.
 import logging
-from typing import Optional
+from typing import Literal, Optional
 
 from pydantic import BaseModel, ConfigDict, NonNegativeFloat, NonNegativeInt
 
@@ -31,8 +31,8 @@ class ExpConfig(BaseModel):
     message_size_bytes: NonNegativeInt = 1000
     delay_seconds: NonNegativeFloat = 2.0
     connect_to: NonNegativeInt = 2
-    muxer: str = "yamux"  # yamux | mplex | quic
-    discovery: str = "static"  # static (CONNECTTO dial) | kad-dht (bootstrap anchor)
+    muxer: Literal["yamux", "mplex", "quic"] = "yamux"
+    discovery: Literal["static", "kad-dht"] = "static"  # CONNECTTO dial vs kad bootstrap
     start_sleep: NonNegativeInt = 60  # node STARTSLEEP before mesh formation
     # Timing (simulated seconds). Publisher starts after the mesh forms (~60s).
     publisher_start_s: NonNegativeInt = 90

src/deployments/shadow/builders.py

@@ -1,6 +1,6 @@
 # Builders for Shadow simulator runs: config values -> kubernetes-client objects
 # and yaml dicts. Pure data, no I/O. See the "Using Shadow at DST" runbook.
-from typing import Optional
+from typing import Literal, Optional
 
 from kubernetes.client import (
     V1Capabilities,
@@ -48,8 +48,8 @@ def render_shadow_yaml(
     sim_stop_time_s: int,
     publisher_start_s: int,
     connect_to: int = 2,
-    muxer: str = "yamux",
-    discovery: str = "static",
+    muxer: Literal["yamux", "mplex", "quic"] = "yamux",
+    discovery: Literal["static", "kad-dht"] = "static",
     start_sleep: int = 60,
     metrics_interval_s: int = 15,
     seed: int = 1,