Central registry of every string that can appear as ViewerEventCounter.EventKey
or catalog EventType. All 12 top-level prefixes from the achievement/mission
seed JSON are constants; Practice.WinAll and Story.ChapterFinishAll are
hierarchical builders that emit multi-level counter keys per event.
Practice.WinAll translates the wire (difficulty:int, enemy_class_id:int) tuple
into the catalog-facing named form (elite/elite2/elite3 : arisa/erika/...).
Wire difficulty 4/6/7 map to elite/elite2/elite3 (verified via
practicetext.json + practice-opponents.json + practice_ai_setting.csv). Class
1-8 map to the leader names in CardClass ordering. Wire values outside the
known set skip that hierarchical level but still advance the top-level counter.
MissionEventKeys.IsRegistered validates that a string starts with a registered
top-level prefix — for seed-importer drift checks in the next commit.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
e1b38d5649