biomech theme: self-host Oxanium 400/700 webfont (task sa)

- Add Oxanium-Regular.woff2 and Oxanium-Bold.woff2 (latin + latin-ext
  subset, ~22 KB total) by Tyler Finck, fetched 2026-05-01 from
  https://gwfh.mranftl.com/fonts/oxanium (mirrors Google Fonts);
  released under SIL OFL 1.1.
- biomech/theme.css: add @font-face blocks pointing at the local
  files. The CSS already declared 'Oxanium' as the body font but
  the family was never loaded, so it silently fell back to system
  sans-serif. Now the geometric techy face actually renders.
- biomech/FONT_LICENSE.txt: full attribution + OFL link + source
  URL + fetch date so future maintainers can re-fetch deterministically.
- templates/embed.go: append themes/*/*.woff2 to the //go:embed glob
  (deferred from task ra because go:embed requires every pattern to
  match at least one file, which biomech now satisfies).
- README.md: append biomech entry to the bundled-fonts bullet list.

Self-hosted, no third-party CDN requests at page load; verified via
grep -RnE 'googleapis|gstatic|@import url\(http' against both source
and generated dist.

Amp-Thread-ID: https://ampcode.com/threads/T-019de000-c062-73c5-9afc-c9af422473cf
Co-authored-by: Amp <amp@ampcode.com>

6 files changed, 59 insertions, 5 deletions

diff --git a/README.md b/README.md
index 439224a..eb49551 100644
--- a/README.md
+++ b/README.md
@@ -128,6 +128,10 @@ Bundled web fonts:
   [Ultimate Oldschool PC Font Pack v2.2](https://int10h.org/oldschool-pc-fonts/),
   [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).
   See [internal/generator/templates/themes/dos/FONT_LICENSE.txt](internal/generator/templates/themes/dos/FONT_LICENSE.txt).
+- **biomech** — *Oxanium* Regular + Bold (.woff2, latin+latin-ext) by
+  Tyler Finck, from [Google Fonts](https://fonts.google.com/specimen/Oxanium),
+  [SIL OFL 1.1](https://openfontlicense.org/open-font-license-official-text/).
+  See [internal/generator/templates/themes/biomech/FONT_LICENSE.txt](internal/generator/templates/themes/biomech/FONT_LICENSE.txt).
 
 When adding a new bundled font:
 
diff --git a/internal/generator/templates/embed.go b/internal/generator/templates/embed.go
index a402a71..56fc673 100644
--- a/internal/generator/templates/embed.go
+++ b/internal/generator/templates/embed.go
@@ -31,12 +31,10 @@ import (
 // and writeThemeAsset.
 //
 // NOTE on the embed glob below: //go:embed requires every pattern to
-// match at least one file, so each font extension is only added once
-// the first theme actually ships such a file. When you introduce the
-// first .woff2 file (or any new extension), append the matching glob
-// here, e.g.:  themes/*/*.woff2
+// match at least one file. When you introduce a new font extension
+// that no other theme uses yet, append the matching glob here.
 //
-//go:embed shell.tmpl shared/*.tmpl shared/shared.css shared/shared.js themes/*/theme.css themes/*/theme.js themes/*/meta.json themes/*/sounds.json themes/*/*.woff themes/*/FONT_LICENSE.txt
+//go:embed shell.tmpl shared/*.tmpl shared/shared.css shared/shared.js themes/*/theme.css themes/*/theme.js themes/*/meta.json themes/*/sounds.json themes/*/*.woff themes/*/*.woff2 themes/*/FONT_LICENSE.txt
 var FS embed.FS
 
 // themeStandardFiles lists the per-theme files that have dedicated
diff --git a/internal/generator/templates/themes/biomech/FONT_LICENSE.txt b/internal/generator/templates/themes/biomech/FONT_LICENSE.txt
new file mode 100644
index 0000000..4aab555
--- /dev/null
+++ b/internal/generator/templates/themes/biomech/FONT_LICENSE.txt
@@ -0,0 +1,35 @@
+Oxanium
+=======
+
+This directory bundles the web font:
+
+    Oxanium-Regular.woff2  (weight 400)
+    Oxanium-Bold.woff2     (weight 700)
+
+Subsets: latin, latin-ext.
+
+Source / version
+----------------
+- Family page : https://fonts.google.com/specimen/Oxanium
+- Designer    : Tyler Finck
+- Webfont set : oxanium-v21 (latin + latin-ext, woff2)
+- Fetched via : https://gwfh.mranftl.com/fonts/oxanium (Webfonts Helper)
+- Fetched on  : 2026-05-01
+
+License
+-------
+SIL Open Font License, Version 1.1.
+
+  - Summary    : https://scripts.sil.org/cms/scripts/page.php?item_id=OFL_web
+  - Full text  : https://openfontlicense.org/open-font-license-official-text/
+  - Project    : https://github.com/sevmeyer/oxanium
+
+The OFL allows free use, modification, and redistribution of the font,
+including embedding in commercial products. Any standalone modified
+version of the font itself must be released under the same license and
+must not use the Reserved Font Name "Oxanium".
+
+Required attribution
+--------------------
+Font: "Oxanium" by Tyler Finck — https://github.com/sevmeyer/oxanium
+      Licensed under the SIL Open Font License 1.1.
diff --git a/internal/generator/templates/themes/biomech/Oxanium-Bold.woff2 b/internal/generator/templates/themes/biomech/Oxanium-Bold.woff2
new file mode 100644
index 0000000..9f50ada
--- /dev/null
+++ b/internal/generator/templates/themes/biomech/Oxanium-Bold.woff2
diff --git a/internal/generator/templates/themes/biomech/Oxanium-Regular.woff2 b/internal/generator/templates/themes/biomech/Oxanium-Regular.woff2
new file mode 100644
index 0000000..eb1f382
--- /dev/null
+++ b/internal/generator/templates/themes/biomech/Oxanium-Regular.woff2
diff --git a/internal/generator/templates/themes/biomech/theme.css b/internal/generator/templates/themes/biomech/theme.css
index 6487149..50d9fcf 100644
--- a/internal/generator/templates/themes/biomech/theme.css
+++ b/internal/generator/templates/themes/biomech/theme.css
@@ -1,3 +1,20 @@
+        /* Self-hosted web font: Oxanium by Tyler Finck (SIL OFL 1.1).
+           Source: https://fonts.google.com/specimen/Oxanium
+           See FONT_LICENSE.txt in this directory. */
+        @font-face {
+            font-family: 'Oxanium';
+            src: url('Oxanium-Regular.woff2') format('woff2');
+            font-weight: 400;
+            font-style: normal;
+            font-display: swap;
+        }
+        @font-face {
+            font-family: 'Oxanium';
+            src: url('Oxanium-Bold.woff2') format('woff2');
+            font-weight: 700;
+            font-style: normal;
+            font-display: swap;
+        }
         :root { --bone:#d0c7bb; --flesh:#803f5d; --vein:#f55b7d; --acid:#93ffd8; --steel:#2d3642; --bg:#09070d; }
         * { margin:0; padding:0; box-sizing:border-box; }
         body { font-family:'Oxanium',system-ui,sans-serif; background:var(--bg); color:var(--bone); overflow:hidden; height:100vh; height:100dvh; }