Initial TTRPG character meta-builder with visual sheet editor.

Offline Electron app seeds 10 system presets, supports create-from-scratch designer with palette/drag/resize/bricks, and exports .ttrpg-system.json for the player.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/shared/index.ts

@@ -0,0 +1,6 @@
+export * from './types.ts';
+export * from './formula.ts';
+export * from './derived.ts';
+export * from './creation.ts';
+export * from './snapshot.ts';
+export * from './systemValidate.ts';