introduce images.tldraw.xyz image optimisation worker (#4069)

Fixes asset loading/processing on staging/previews by introducing a new
image processing worker. This worker acts as a proxy for our various
image hosts and resizes/optimizes/caches images on the fly. Like the old
bookmark worker, this one is deployed in an ad-hoc fashion as it works
across environments and we're not likely to change it often.

### Change type

- [x] `other`

scripts/deploy-dotcom.ts

@@ -29,30 +29,30 @@ const dotcom = path.relative(process.cwd(), path.resolve(__dirname, '../apps/dot
 // `env` instead. This makes sure that all required env vars are present.
 const env = makeEnv([
 	'APP_ORIGIN',
-	'ASSET_UPLOAD',
 	'ASSET_UPLOAD_SENTRY_DSN',
-	'ASSET_BUCKET_ORIGIN',
+	'ASSET_UPLOAD',
 	'CLOUDFLARE_ACCOUNT_ID',
 	'CLOUDFLARE_API_TOKEN',
 	'DISCORD_DEPLOY_WEBHOOK_URL',
 	'DISCORD_HEALTH_WEBHOOK_URL',
-	'HEALTH_WORKER_UPDOWN_WEBHOOK_PATH',
 	'GC_MAPS_API_KEY',
+	'GH_TOKEN',
+	'HEALTH_WORKER_UPDOWN_WEBHOOK_PATH',
+	'IMAGE_WORKER',
+	'MULTIPLAYER_SERVER',
+	'R2_ACCESS_KEY_ID',
+	'R2_ACCESS_KEY_SECRET',
 	'RELEASE_COMMIT_HASH',
 	'SENTRY_AUTH_TOKEN',
-	'SENTRY_DSN',
 	'SENTRY_CSP_REPORT_URI',
+	'SENTRY_DSN',
 	'SUPABASE_LITE_ANON_KEY',
 	'SUPABASE_LITE_URL',
 	'TLDRAW_ENV',
-	'VERCEL_PROJECT_ID',
 	'VERCEL_ORG_ID',
+	'VERCEL_PROJECT_ID',
 	'VERCEL_TOKEN',
 	'WORKER_SENTRY_DSN',
-	'MULTIPLAYER_SERVER',
-	'GH_TOKEN',
-	'R2_ACCESS_KEY_ID',
-	'R2_ACCESS_KEY_SECRET',
 ])
 
 const discord = new Discord({
@@ -148,6 +148,7 @@ async function prepareDotcomApp() {
 			ASSET_UPLOAD: previewId
 				? `https://${previewId}-tldraw-assets.tldraw.workers.dev`
 				: env.ASSET_UPLOAD,
+			IMAGE_WORKER: env.IMAGE_WORKER,
 			MULTIPLAYER_SERVER: previewId
 				? `https://${previewId}-tldraw-multiplayer.tldraw.workers.dev`
 				: env.MULTIPLAYER_SERVER,