DiceRollHistory stores the last 20 rolls in reverse chronological order (label, pool size, results, successes, sequence number). A History icon in the top app bar opens a dialog listing all rolls. CharacterSheetPage records each dice roll via onRecordRoll callback. Includes 9 unit tests for history ordering, capacity, and clearing. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>