Brief Summary: This randomized controlled trial aims to evaluate whether active remote symptom monitoring and management via a smartphone app utilizing electronic patient-reported outcomes (ePRO) can improve adherence to prescribed outpatient pulmonary rehabilitation exercises among postsurgical lung cancer patients. Eligible patients will use the app for perioperative care and be randomized to an intervention group receiving ePRO-based symptom monitoring with clinician feedback or a control group receiving ePRO without feedback. The primary outcome is rehabilitation exercise adherence rate over 1 month after discharge. If proven effective, the app-enabled remote rehabilitation model can be scaled up to enhance recovery for more postoperative patients. Due to slower-than-expected recruitment, an interim analysis was introduced through a protocol amendment. The amendment was approved by the Ethics Committee before conducting the analysis, and the plan was incorporated into the updated study record. The interim review evaluated feasibility and informed the addition of mean weekly exercise duration as a co-primary endpoint with adjusted statistical thresholds.