Fix service workers

site/.env.example

@@ -5,6 +5,11 @@ PUBLIC_SITE_URL=https://example.com
 PUBLIC_UMAMI_SCRIPT_URL=https://analytics.example.com/script.js
 PUBLIC_UMAMI_WEBSITE_ID=00000000-0000-0000-0000-000000000000
 
+# Service worker toggle (public, build-time). Use to enable in prod/staging.
+# - In `npm run dev`, service workers are not registered regardless.
+# - In `npm run build`/`preview`, SW is registered only if this is "true".
+PUBLIC_ENABLE_SW=true
+
 # Content ingestion configuration (used by scripts)
 YOUTUBE_CHANNEL_ID=UCxxxxxxxxxxxxxxxxxxxxxx
 YOUTUBE_API_KEY=

site/src/env.d.ts

@@ -4,6 +4,7 @@ interface ImportMetaEnv {
   readonly PUBLIC_SITE_URL?: string;
   readonly PUBLIC_UMAMI_SCRIPT_URL?: string;
   readonly PUBLIC_UMAMI_WEBSITE_ID?: string;
+  readonly PUBLIC_ENABLE_SW?: string;
 }
 
 interface ImportMeta {

site/src/layouts/BaseLayout.astro

@@ -57,8 +57,9 @@ const canonicalUrl = `${siteUrl}${canonicalPath.startsWith("/") ? canonicalPath
     }
 
     {
-      // Register SW only in production builds (Astro sets import.meta.env.PROD at build time).
-      import.meta.env.PROD ? (
+      // Register SW only in production builds (Astro sets import.meta.env.PROD at build time)
+      // and only when explicitly enabled by env.
+      import.meta.env.PROD && import.meta.env.PUBLIC_ENABLE_SW === "true" ? (
         <script is:inline>
           {`
           if ("serviceWorker" in navigator) {