feat(deskclaw): rebrand + vibe presets + chat model picker

electron/utils/agent-config.ts

@@ -681,6 +681,31 @@ export async function updateAgentModel(agentId: string, modelRef: string | null)
   });
 }
 
+export async function updateDefaultModel(modelRef: string | null): Promise<AgentsSnapshot> {
+  return withConfigLock(async () => {
+    const config = await readOpenClawConfig() as AgentConfigDocument;
+    const { agentsConfig } = normalizeAgentsConfig(config);
+    const normalizedModelRef = typeof modelRef === 'string' ? modelRef.trim() : '';
+    const nextAgentsConfig: AgentsConfig = { ...(agentsConfig || {}) };
+    const nextDefaults: AgentDefaultsConfig = { ...(nextAgentsConfig.defaults || {}) };
+
+    if (!normalizedModelRef) {
+      delete nextDefaults.model;
+    } else {
+      if (!isValidModelRef(normalizedModelRef)) {
+        throw new Error('modelRef must be in "provider/model" format');
+      }
+      nextDefaults.model = { primary: normalizedModelRef };
+    }
+
+    nextAgentsConfig.defaults = nextDefaults;
+    config.agents = nextAgentsConfig;
+    await writeOpenClawConfig(config);
+    logger.info('Updated default model', { modelRef: normalizedModelRef || null });
+    return buildSnapshotFromConfig(config);
+  });
+}
+
 export async function deleteAgentConfig(agentId: string): Promise<{ snapshot: AgentsSnapshot; removedEntry: AgentListEntry }> {
   return withConfigLock(async () => {
     if (agentId === MAIN_AGENT_ID) {