fix(delegate-task): add token counting and truncation to prevent context overflow

Fixes #1815, #1733

src/config/schema/categories.ts

@@ -20,6 +20,7 @@ export const CategoryConfigSchema = z.object({
   textVerbosity: z.enum(["low", "medium", "high"]).optional(),
   tools: z.record(z.string(), z.boolean()).optional(),
   prompt_append: z.string().optional(),
+  max_prompt_tokens: z.number().int().positive().optional(),
   /** Mark agent as unstable - forces background mode for monitoring. Auto-enabled for gemini/minimax models. */
   is_unstable_agent: z.boolean().optional(),
   /** Disable this category. Disabled categories are excluded from task delegation. */