fix(logging): cap file logs with configurable maxFileBytes

Co-authored-by: Xinhua Gu <562450+xinhuagu@users.noreply.github.com>

src/config/zod-schema.ts

@@ -190,6 +190,7 @@ export const OpenClawSchema = z
           ])
           .optional(),
         file: z.string().optional(),
+        maxFileBytes: z.number().int().positive().optional(),
         consoleLevel: z
           .union([
             z.literal("silent"),