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

apps/solvecraft-web/index.html

@@ -5,6 +5,8 @@
   <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
   <title>SolidCraft</title>
   <link data-trunk rel="rust" data-bin="solvecraft-web" data-wasm-opt="z" data-weak-refs />
+  <link data-trunk rel="copy-file" href="fonts/BIZUDPGothic-Regular.ttf" data-target-path="fonts" />
+  <link data-trunk rel="copy-file" href="fonts/OFL.txt" data-target-path="fonts" />
   <style>
     html, body { margin: 0; padding: 0; width: 100%; height: 100%; overflow: hidden; background: #e8ebf0; }
     #solvecraft_canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }