feat: implement series/plan discovery, celebrations, and 3-dot manage…

[rinzinDev]

feat: implement series/plan discovery, celebrations, and 3-dot management overlays (#269)

• Rebuild Home screen with personalized greeting, FeaturedSeriesCard, and ContinueTodayCard
• Rebuild Series Detail screen with hero image, About section, creator info, and sticky Enroll button
• Add 3-dot options sheet (About, Reminders, Unenroll) to Plan landing screen
• Add Reminders sheet with Cupertino/Material time picker and toggle
• Add series breadcrumb, "ABOUT THIS PLAN" section, and ON TRACK!/status badges to Plan landing
• Implement Daily, Plan, and Series celebration modals matching Figma design
• Polish Day Carousel with Last day label and theme-aware selection style
• Add 35+ localization keys across EN, Tibetan, and Chinese for all new UI