fix(delegate-task): reject stray backend-style categories

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/delegate-task/tools.ts

@@ -101,7 +101,7 @@ export function createDelegateTask(options: DelegateTaskToolOptions): ToolDefini
       description: tool.schema.string().describe("Short task description (3-5 words)"),
       prompt: tool.schema.string().describe("Full detailed prompt for the agent"),
       run_in_background: tool.schema.boolean().describe("REQUIRED. true=async (returns task_id), false=sync (waits). Use false for task delegation, true ONLY for parallel exploration."),
-      category: tool.schema.string().optional().describe(`REQUIRED if subagent_type not provided. Do NOT provide both category and subagent_type.`),
+      category: tool.schema.enum(categoryNames).optional().describe(`REQUIRED if subagent_type not provided. Do NOT provide both category and subagent_type.`),
       subagent_type: tool.schema.string().optional().describe("REQUIRED if category not provided. Do NOT provide both category and subagent_type. Must be a callable non-primary agent name returned by app.agents()."),
       session_id: tool.schema.string().optional().describe("Existing Task session to continue"),
       command: tool.schema.string().optional().describe("The command that triggered this task"),