Mount templates/custom/ directly to Gitea's default GITEA_CUSTOM templates
path. No entrypoint override or envsubst needed.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Injects the Umami tracking script into every Gitea page using a custom
header.tmpl generated at startup via envsubst. Script URL and website ID
are externalized to UMAMI_SCRIPT_URL / UMAMI_WEBSITE_ID env vars.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>