Fonts: use craft-fonts as an optional build input; move the Japanese fonts out

Shippori Mincho (assets/fonts, from #145) moves to storytold/craft-fonts. crates/text/build.rs
embeds the fonts of a craft-fonts checkout when CRAFT_FONTS_DIR is set (web: BIZ UDPGothic
Regular only) as vectorcraft_text::CRAFT_FONTS; unset, it is empty and Japanese falls back to the
installed fonts. Document text gets the Japanese faces after the bundled fonts (Mincho first); the
UI adds them at the end of every egui family (BIZ UDPGothic first), before ui_fonts' system-font
discovery. Release and FreeBSD CI builds check craft-fonts out at a pinned commit; packages carry
the fonts' OFL texts.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

CLAUDE.md

@@ -22,6 +22,7 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
     - Creative Commons with redistribution allowed.
   - **Every asset file must have a row in [`ASSETS.md`](ASSETS.md)** (path, author, source URL, licence, notes). Put licence texts next to the assets (e.g. `assets/fonts/OFL-*.txt`) and summarize them in `NOTICE`.
   - `cargo xtask assets` (run by `cargo xtask ci`) fails on any unattributed asset.
+  - **Fonts live in [storytold/craft-fonts](https://github.com/storytold/craft-fonts), never in this repo** (rules: craftrules [`standards/fonts.md`](https://github.com/storytold/craftrules/blob/main/standards/fonts.md)). Never commit a font file here; add new fonts to craft-fonts. The app uses it only through the optional `CRAFT_FONTS_DIR` build option (`CRAFT_FONTS_DIR=../craft-fonts cargo xtask ci`, path relative to the workspace root), read by `crates/text/build.rs` into `vectorcraft_text::CRAFT_FONTS`; never add it to a `Cargo.toml`. Everything must build, test and run with `CRAFT_FONTS` empty, and tests of its glyphs skip when it is. Details: `docs/development.md` › Fonts.
   - Code and original assets are MIT OR Apache-2.0 (`LICENSE-MIT`, `LICENSE-APACHE`, `NOTICE`). The ArtCraft logos in `docs/brand/` are trademarks, not open source, under `docs/brand/LICENSE-brand.txt`: never modify them or use them outside VectorCraft.
   - Prefer art generated in code for defaults (swatches, brushes, symbols, patterns, cursors). If the provenance of an asset is unclear, don't add it.
   - Reference screenshots of Illustrator stay local under the gitignored `plan/` and are never committed, published or used as assets.