feat(site): redesigned /download, releases and links moved from GitHub to Forgejo

- /download: the jar as an in-game item (pixel heart in an inventory slot, vanilla-style tooltip with version, size and SHA-256, copy button), spec list, three install steps, release timeline
- releases read through a cached nginx proxy (/api/releases): Forgejo's API has no CORS headers
- README, footer and landing links point to git.wihuk.pro/boba/LoVisual (the GitHub repo they used does not exist)
- release workflow publishes through the Forgejo API and ships lovisual.jar.sha256
- fix i18n interpolation placeholders ({{x}}) in the download strings

backend/deploy/nginx-visual.loki-code.dev.conf

@@ -3,6 +3,21 @@ server {
     root /var/www/visual.loki-code.dev/html;
     index index.html;
 
+    # Forgejo's API sends no CORS headers, so the download page reads the
+    # release list through this cached proxy (5 min) instead of from the browser.
+    location = /api/releases {
+        proxy_pass https://git.wihuk.pro/api/v1/repos/boba/LoVisual/releases?limit=10;
+        proxy_ssl_server_name on;
+        proxy_set_header Host git.wihuk.pro;
+        proxy_set_header Authorization "";
+        proxy_set_header Cookie "";
+        proxy_hide_header Set-Cookie;
+        proxy_cache lv_releases;
+        proxy_cache_valid 200 5m;
+        proxy_cache_use_stale error timeout updating http_500 http_502 http_503;
+        add_header Cache-Control "public, max-age=60" always;
+    }
+
     location /api/ {
         proxy_pass http://127.0.0.1:8080/;
         proxy_http_version 1.1;