refactor(image): pick provider from NUXT_IMAGE_PROVIDER build variable

Replace the implicit `WORKERS_CI_BRANCH === 'release'` branch-name check
with an explicit `NUXT_IMAGE_PROVIDER` build variable, set per Wrangler
environment in Cloudflare Workers Builds. The `production` environment
sets it to `cloudflare`; preview and local builds leave it unset and
fall back to `none`.

Also drop the stale `NUXT_IMAGE_PROVIDER` entry from the Worker
`vars` — it was a runtime var that nothing read, and keeping it next to
the new build variable of the same name was just confusing.

https://claude.ai/code/session_01TWED5ZjQD6uv434RqTBaY2

Author: claude

nuxt.config.ts

@@ -3,11 +3,15 @@ import {defineOrganization} from 'nuxt-schema-org/schema'
 import tailwindcss from "@tailwindcss/vite";
 import pkg from './package.json' assert {type: 'json'}
 
-// Cloudflare Workers Builds deploys the `release` branch as production and
-// every other branch (incl. `main`) as a preview. The Cloudflare image proxy
-// (img.onelitefeather.net) only serves the live site, so preview deploys must
-// not route images through it — otherwise every branch-new asset 404s.
-const isProductionImageHost = process.env.WORKERS_CI_BRANCH === 'release'
+// Image provider is chosen at build time from the NUXT_IMAGE_PROVIDER build
+// variable, set per Wrangler environment in Cloudflare Workers Builds. The
+// `production` environment sets it to `cloudflare` to route images through
+// the img.onelitefeather.net proxy; preview/local builds leave it unset and
+// fall back to `none`, serving the originals straight from the deploy's own
+// /public — the proxy only knows the live site and would 404 branch assets.
+const imageProvider = process.env.NUXT_IMAGE_PROVIDER === 'cloudflare'
+  ? 'cloudflare'
+  : 'none'
 
 export default defineNuxtConfig({
     compatibilityDate: '2025-05-15',
@@ -131,10 +135,10 @@ export default defineNuxtConfig({
         version: pkg.version
     },
     image: {
-        // Production routes images through the Cloudflare image proxy; preview
-        // and local builds use the `none` provider so originals are served
-        // straight from the deployment's own /public, which always exists.
-        provider: isProductionImageHost ? 'cloudflare' : 'none',
+        // Provider is resolved from the NUXT_IMAGE_PROVIDER build variable
+        // (see the note at the top of this file). `cloudflare` on production,
+        // `none` everywhere else.
+        provider: imageProvider,
         // Prefer modern formats with automatic fallback for browsers that don't support them.
         format: ['avif', 'webp'],
         // Slightly lower default quality to trim payloads without obvious visual loss.
@@ -305,10 +309,10 @@ export default defineNuxtConfig({
                             database_name: 'launchpad',
                             database_id: 'a92127c1-aaa3-4753-82ba-ea59fa9e7140'
                         }
-                    ],
-                    vars: {
-                        "NUXT_IMAGE_PROVIDER": "cloudflare",
-                    }
+                    ]
+                    // NUXT_IMAGE_PROVIDER is a Cloudflare Workers Builds build
+                    // variable (read at build time in nuxt.config, see top of
+                    // file) — not a runtime Worker var, so it is not in `vars`.
                 }
             }
         }