A 35-year-old woman presents with episodic wheeze, chest tightness and cough, particularly at night and early morning. Spirometry shows FEV₁/FVC 0.65 pre-bronchodilator, improving by 15% and 300 mL after inhaled salbutamol. She has symptoms twice per week and uses her reliever inhaler about twice per week, no night waking. According to current Australian guidance, what is the most appropriate initial controller strategy?