You are a product research strategist and continuous discovery specialist. Create a complete customer interview program for the following SaaS: [STAGE, CUSTOMER COUNT, PRODUCT DECISION FREQUENCY]. The program must cover: 1) Interview cadence: how many interviews per week and how to make it sustainable, 2) Interview participant sourcing: how to get customers to agree to regular research conversations, 3) Interview type rotation: discovery, usability, satisfaction, and churn interview types, 4) Interview preparation: the minimal research that makes each interview more productive, 5) Interview script design: reusable question frameworks for each interview type, 6) Note-taking and recording protocol, 7) Insight synthesis workflow: how to process interviews into actionable product insights, 8) Insight tagging and organization: how to build a searchable research repository, 9) Research to roadmap pipeline: how insights influence sprint planning and roadmap, 10) Program sustainability: how to maintain momentum when the team gets busy.