You can eat most anything you want to. All you need to be careful with is antacid medicines.
The first person you should ask these questions to is your doctor.
The bottom line is, eat a healthy diet. Nothing in a healthy diet is going to affect Harvoni. A fact sheet from Gilead is readily available on the web that details any contraindications of Harvoni.
Some people have had spikes in blood pressure while on Harvoni, so a lower sodium diet may be wise as a preventive measure. Having said that, you should see your health care practitioner to determine whether this is even necessary in your case.