refactor: centralize main session key resolution

src/config/sessions.ts

@@ -19,6 +19,7 @@ import {
   isCacheEnabled,
   resolveCacheTtlMs,
 } from "./cache-utils.js";
+import { loadConfig } from "./config.js";
 import { resolveStateDir } from "./paths.js";
 
 // ============================================================================
@@ -232,6 +233,10 @@ export function resolveMainSessionKey(cfg?: {
   return buildAgentMainSessionKey({ agentId, mainKey });
 }
 
+export function resolveMainSessionKeyFromConfig(): string {
+  return resolveMainSessionKey(loadConfig());
+}
+
 export { resolveAgentIdFromSessionKey };
 
 export function resolveAgentMainSessionKey(params: {