fix: mount custom.css to assets directory, not css

static_paths only includes: assets, fonts, images, js
The css directory is NOT served by Phoenix.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

asciinema/compose.yaml

@@ -8,7 +8,7 @@ services:
     volumes:
       - asciinema_data:/var/opt/asciinema
       - ./custom.exs:/opt/app/etc/custom.exs:ro
-      - ./theme/custom.css:/opt/app/lib/asciinema-1.0.0/priv/static/css/custom.css:ro
+      - ./theme/custom.css:/opt/app/lib/asciinema-1.0.0/priv/static/assets/custom.css:ro
       - ./theme/favicon.svg:/opt/app/lib/asciinema-1.0.0/priv/static/images/favicon-custom.svg:ro
       - ./theme/custom.js:/opt/app/lib/asciinema-1.0.0/priv/static/js/custom.js:ro
     environment: