This repository is a production-grade React calendar component library (`@ilamy/calendar`) designed as a lightweight (~13 KB gzipped) replacement for FullCalendar. It provides month, week, day, year, and agenda views with drag-and-drop, resource scheduling, RFC 5545 recurring events, iCal export, and internationalization. The core ships no CSS and relies on Tailwind CSS v4 with shadcn/ui tokens, making it themeable and tree-shakeable. Architecturally, the library follows a plugin-first pattern: the core implements a pluggable kernel (`IlamyPlugin` interface) that accepts opt-in plugins for recurrence, agenda, and drag-to-create. Each plugin contributes views, event transformations, mutation scopes, and UI slots through a runtime composer. The state management uses a single `CalendarProvider` context that composes four engine slices (config, navigation, data, interaction). The view system is built on two grid primitives (vertical-grid for time-based layouts, horizontal-grid for date-based layouts) that are shared across all views and test harnesses. The codebase demonstrates strong engineering discipline: a huge unit test suite (995+ tests) with regression pinning against issue numbers, deterministic Playwright E2E tests, a CI pipeline with lint/build/type-check/test gates, and agent-driven code review skills. However, there is some duplication of UI primitives between packages, and the dependency on a custom dayjs wrapper for timezone handling introduces fragility. The library is actively maintained with frequent releases and detailed changelogs.