ui: relative api paths so /infra/svc-proxy/ proxying works

Absolute /api/* resolved against the dashboard origin, hitting
server-manager's 404 instead of the proxied svc-proxy. Switch to
./api/* so they land under the same /infra/svc-proxy/ prefix.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/httpsrv/static/index.html

@@ -131,7 +131,7 @@ const fmtAgo = secs => {
 
 async function refreshConnections() {
   try {
-    const r = await fetch('/api/connections');
+    const r = await fetch('./api/connections');
     const j = await r.json();
     const rows = document.getElementById('conn-rows');
     const empty = document.getElementById('conn-empty');
@@ -172,7 +172,7 @@ refreshConnections();
 function startLogStream() {
   const status = document.getElementById('status');
   const box = document.getElementById('logbox');
-  const es = new EventSource('/api/logs');
+  const es = new EventSource('./api/logs');
   es.onopen = () => { status.textContent = 'log stream: live'; status.className = 'status ok'; };
   es.onerror = () => { status.textContent = 'log stream: reconnecting'; status.className = 'status err'; };
   es.onmessage = ev => {