Manages bidirectional synchronization between PD20_Automaton_PLC交握表.xlsx (PC UI development interface specification) and 50-layer markdown documentation (PLC memory mapping). Use when (1) Syncing signals from work logs to Excel and markdown, (2) Detecting conflicts in memory address allocation, (3) Checking consistency between Excel and markdown, (4) Updating Excel based on markdown changes, (5) Updating markdown based on Excel changes, (6) Any task involving PD20 PLC memory mapping management, signal definition updates, or PC-PLC interface synchronization. This skill manages CRUD operations on both Excel and markdown files, with emphasis on conflict detection and semi-automated workflows requiring user confirmation.