feat(web): self-host Japanese font and load on-demand without external CDN

- Bundle BIZ UDPGothic Regular (SIL OFL 1.1) exclusively in solvecraft-web dist

- Remove external jsDelivr CDN fallback; fetch font solely from same-origin ./fonts/

- Fetch Japanese font on-demand only when UI language is set to Japanese

- Gracefully fall back to English UI on fetch failure to prevent tofu glyphs

- Update ATTRIBUTION.md, NOTICE, and THIRD-PARTY-LICENSES.txt

NOTICE

@@ -19,8 +19,9 @@ licensed MIT OR Apache-2.0; ATTRIBUTION.md lists the files.
 The release packaging (.github/workflows/release.yml, packaging/) is adapted from PhotoCraft
 (https://github.com/storytold/photocraft), licensed under the Apache License 2.0.
 
-None of the bundled assets come from third parties: every icon is drawn in code. The per-file
-list is in ATTRIBUTION.md.
+Most bundled assets are drawn in code or contributed originally; third-party fonts (Liberation Sans
+for sketch text, BIZ UDPGothic for web Japanese display) are licensed under SIL OFL 1.1. The
+per-file list is in ATTRIBUTION.md.
 
 SolveCraft is an independent project and is not affiliated with, sponsored by or endorsed by
 Autodesk, Inc. Autodesk and Fusion are trademarks of Autodesk, Inc.; they are used here only to