Consolidate MangaCircus app, scraper, and Compose baseline

tools/healthcheck.js

@@ -0,0 +1,5 @@
+'use strict';
+const ports = { reader: process.env.PORT || 8080, scraper: process.env.SCRAPER_PORT || 8091, sentinel: process.env.SENTINEL_PORT || 8092 };
+const service = process.argv[2] || 'reader';
+fetch(`http://127.0.0.1:${ports[service]}/health`, { signal: AbortSignal.timeout(4000) })
+  .then(async r => { const body = await r.json(); if (!r.ok || !body.ok) process.exitCode = 1; }).catch(() => { process.exitCode = 1; });