Fix four bugs and add logo/branding polish

- docker-compose: add register-user service (profiles: [tools]) with YAML anchor to avoid env duplication
- src/index.ts: show localhost instead of 0.0.0.0 in startup message
- file-view: render <img> inline for image/* MIME types
- file-list: add Copy link button per row (requires baseUrl param)
- layout: add hideLogo option; file view page hides the logo
- style.css: remove uppercase from .logo (Nanodrop not NANODROP), add button.copy-link styles, add .file-view img styles, widen last td

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/index.ts

@@ -12,7 +12,8 @@ const app = createServer({ config, db });
 
 try {
   await app.listen({ port: config.port, host: config.host });
-  console.log(`Nanodrop running on http://${config.host}:${config.port}`);
+  const displayHost = config.host === '0.0.0.0' ? 'localhost' : config.host;
+  console.log(`Nanodrop running on http://${displayHost}:${config.port}`);
 } catch (err) {
   console.error(err);
   process.exit(1);