fix(agents): restore canonical core agent ordering

Remap the core agent keys, default agent, and command routing back to\nlist display names so OpenCode's name-based sorting keeps the\ncanonical Sisyphus -> Hephaestus -> Prometheus -> Atlas order.\n\nAlso teach tool config lookups to resolve the prefixed list keys and\nadd regression tests that exercise the real ordering and routing path.

src/plugin-handlers/command-config-handler.ts

@@ -1,7 +1,7 @@
 import type { OhMyOpenCodeConfig } from "../config";
 import {
   getAgentConfigKey,
-  getAgentDisplayName,
+  getAgentListDisplayName,
 } from "../shared/agent-display-names";
 import {
   loadUserCommands,
@@ -99,7 +99,7 @@ export async function applyCommandConfig(params: {
 function remapCommandAgentFields(commands: Record<string, Record<string, unknown>>): void {
   for (const cmd of Object.values(commands)) {
     if (cmd?.agent && typeof cmd.agent === "string") {
-      cmd.agent = getAgentDisplayName(getAgentConfigKey(cmd.agent));
+      cmd.agent = getAgentListDisplayName(getAgentConfigKey(cmd.agent));
     }
   }
 }