fix: prevent agent deletion from disabling built-ins

Stop delete from creating disable overrides
Delete only the selected agent scope
Keep web and VS Code behavior aligned

packages/ui/src/stores/useAgentsStore.ts

@@ -190,7 +190,7 @@ interface AgentsStore {
   loadAgents: () => Promise<boolean>;
   createAgent: (config: AgentConfig) => Promise<boolean>;
   updateAgent: (name: string, config: Partial<AgentConfig>) => Promise<boolean>;
-  deleteAgent: (name: string) => Promise<boolean>;
+  deleteAgent: (name: string, scope?: AgentScope) => Promise<boolean>;
   getAgentByName: (name: string) => Agent | undefined;
   // Returns only visible agents (excludes hidden internal agents)
   getVisibleAgents: () => Agent[];
@@ -448,7 +448,7 @@ export const useAgentsStore = create<AgentsStore>()(
           }
         },
 
-        deleteAgent: async (name: string) => {
+        deleteAgent: async (name: string, scope?: AgentScope) => {
           startConfigUpdate("Deleting agent configuration…");
           let requiresReload = false;
           try {
@@ -458,7 +458,11 @@ export const useAgentsStore = create<AgentsStore>()(
 
             const response = await runtimeFetch(`/api/config/agents/${encodeURIComponent(name)}${queryParams}`, {
               method: 'DELETE',
-              headers: configDirectory ? { 'x-opencode-directory': configDirectory } : undefined,
+              headers: {
+                'Content-Type': 'application/json',
+                ...(configDirectory ? { 'x-opencode-directory': configDirectory } : {}),
+              },
+              body: JSON.stringify({ scope }),
             });
 
             const payload = await response.json().catch(() => null);