fix(start-work): reuse registered opencode agent names

src/hooks/no-sisyphus-gpt/hook.ts

@@ -1,8 +1,12 @@
 import type { PluginInput } from "@opencode-ai/plugin"
 import { isGptModel, isGpt5_4Model } from "../../agents/types"
-import { getSessionAgent, updateSessionAgent } from "../../features/claude-code-session-state"
+import {
+  getSessionAgent,
+  resolveRegisteredAgentName,
+  updateSessionAgent,
+} from "../../features/claude-code-session-state"
 import { log } from "../../shared"
-import { getAgentConfigKey, getAgentDisplayName } from "../../shared/agent-display-names"
+import { getAgentConfigKey } from "../../shared/agent-display-names"
 
 const TOAST_TITLE = "NEVER Use Sisyphus with GPT"
 const TOAST_MESSAGE = [
@@ -10,8 +14,6 @@ const TOAST_MESSAGE = [
   "Do NOT use Sisyphus with GPT (except GPT-5.4 which has specialized support).",
   "For GPT models (other than 5.4), always use Hephaestus.",
 ].join("\n")
-const HEPHAESTUS_DISPLAY = getAgentDisplayName("hephaestus")
-
 function showToast(ctx: PluginInput, sessionID: string): void {
   ctx.client.tui.showToast({
     body: {
@@ -43,9 +45,9 @@ export function createNoSisyphusGptHook(ctx: PluginInput) {
 
       if (agentKey === "sisyphus" && modelID && isGptModel(modelID) && !isGpt5_4Model(modelID)) {
         showToast(ctx, input.sessionID)
-        input.agent = "hephaestus"
+        input.agent = resolveRegisteredAgentName("hephaestus") ?? "hephaestus"
         if (output?.message) {
-          output.message.agent = "hephaestus"
+          output.message.agent = resolveRegisteredAgentName("hephaestus") ?? "hephaestus"
         }
         updateSessionAgent(input.sessionID, "hephaestus")
       }