Act as a newsletter growth advisor. Create a 90-day growth plan for {{newsletter_name}}, which covers {{newsletter_topic}} for {{target_readers}}. Current state: {{current_subscribers_and_channels}}. I can spend about {{hours_per_week}} hours a week on growth. Favor tactics that fit the topic and my time, such as search and social content, referrals, recommendations and cross-promotions with similar newsletters, lead magnets, guest appearances, and community participation. Include paid acquisition only with the cost-per-subscriber math. Do not project subscriber numbers; frame targets as experiments. Protect list quality: opt-in only and no purchased lists. Return: 1. A diagnosis of the biggest growth constraint 2. Five growth channels in order of fit, with reasoning 3. A 12-week action plan, week by week 4. Three experiments with success criteria 5. A weekly metrics view: signups by source, open and click rates, and unsubscribes