# Implementation Plan - Fix RRULE Object Mapping

## Phase 1: Reproduction [checkpoint: 2fbb260]
- [x] Task: Reproduce `Unknown RRULE property` error 0b67cbb
    - [x] Modify the test case in `icalendar_test.ts` to use `frequency` instead of `freq` in the mock object.
    - [x] Run the test and confirm it fails with the expected error.
- [x] Task: Conductor - User Manual Verification 'Reproduction' (Protocol in workflow.md)

## Phase 2: Fix Implementation [checkpoint: fe28a5c]
- [x] Task: Implement mapping logic in `icalendar.ts` b8bc6cc
    - [x] Create a mapping object for verbose keys to iCal keys.
    - [x] Update `expandRecurrences` to use this mapping.
    - [x] Run the test to confirm it passes.
- [x] Task: Conductor - User Manual Verification 'Fix Implementation' (Protocol in workflow.md)

## Phase 3: Verification & Cleanup [checkpoint: 793326a]
- [x] Task: Full Regression Check 7f9a618
    - [x] Run all tests in `icalendar_test.ts`.
- [x] Task: Conductor - User Manual Verification 'Verification & Cleanup' (Protocol in workflow.md)