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

The Japanese fonts (BIZ UDPGothic Regular/Bold for the UI, BIZ UDMincho for text
watermarks; #110, #114) now come from storytold/craft-fonts instead of assets/fonts/.

- crates/engine/build.rs: the craft-fonts recipe. With CRAFT_FONTS_DIR set it embeds
  the manifest's fonts as lightcraft_engine::CRAFT_FONTS (wasm32: BIZ UDPGothic Regular
  only, for the web size budget); unset, CRAFT_FONTS is empty. Local files only, no
  network; craft-fonts is not in any Cargo.toml.
- UI: theme::font_definitions adds the Japanese faces after Inter and egui's defaults
  in every family (BIZ UDPGothic first, Bold first for semibold). About box lists the
  embedded families.
- Watermarks: Inter, then the craft-fonts Japanese faces (Mincho first).
- Removed BIZUDPGothic-Regular/Bold.ttf, BIZUDMincho-Regular.ttf and their OFL files,
  and their ATTRIBUTION rows; added an attribution row for craft-fonts as an optional
  build input; NOTICE updated.
- Tests: Japanese glyph tests use CRAFT_FONTS and skip without it; new tests for
  Japanese in the UI with craft-fonts and for the UI and watermarks without it.
- CI: the FreeBSD job builds/tests with craft-fonts. Releases check out craft-fonts at
  a pinned commit, build with CRAFT_FONTS_DIR + CRAFT_FONTS_REQUIRED=1, and ship the
  fonts' OFL licences (plus NOTICE) in every package.
- Docs: AGENTS.md, CLAUDE.md, README, docs/web.md, docs/localization-ja.md, ROADMAP,
  parity.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/freebsd.yml

@@ -27,6 +27,12 @@ jobs:
     timeout-minutes: 300
     steps:
       - uses: actions/checkout@v4
+      # Optional font build input, so the Japanese font tests run (they skip without it).
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          repository: storytold/craft-fonts
+          ref: abb83316d96aa59c1cf64784289e378fe9fa5695
+          path: craft-fonts
       - name: Build and test in a FreeBSD VM
         uses: vmactions/freebsd-vm@c46abacb49f09938ca4e1702d15d836285d694cc # v1
         with:
@@ -44,5 +50,6 @@ jobs:
             # The checkout is synced in under another owner; let tests that call git read it.
             git config --global --add safe.directory "*"
             rustc --version
+            export CRAFT_FONTS_DIR="$PWD/craft-fonts" CRAFT_FONTS_REQUIRED=1
             CARGO_PROFILE_DEV_DEBUG=0 cargo build --workspace --all-targets --locked
             CARGO_PROFILE_DEV_DEBUG=0 cargo test --workspace --locked