v0.103.1 — Docs update

Shipped 2026-09-21 — one commit on main (26d9a3e9), tagged v0.103.1; no code. The new character sheet re-specified as an epic of three releases — foundations (v0.105.0), the 5e sheet (v0.106.0), the System 8 sheet (v0.107.0) — with the design the three share (the seam, the sheet-kit, the geometry from the fillable sheet expressed as a reflowing grid, the field editors, the ability-score rule, what the walkthrough needs of the sheet) and its decisions NS-D3 through NS-D10; the creation walkthrough moved to v0.108.0 with its picture written in; the roadmap index's Near-term table and entries updated.