Database connections kept open; a click's wait is measured (#241, #245, #246)

#241: on production, All Subscriptions' query runs in 31 ms, unread oldest-first in 30, the
feed list's count in 5, generic plans included (EXPLAIN ANALYZE, BUFFERS, read only), against
0.3-1.6 s in ipx. A new Postgres connection takes 80-330 ms to open, and a page load asks for
more than are idle: four of six slow loads came as the pool grew (3 to 6, 2 to 6, 3 to 5, 6 to
8), and 20 requests at once took a median 414 ms while the pool grew from 8 to 20. The daemon
and the directory's server now keep their whole pool open (min = max); a command such as `ipx
status`, and the tests, which share the server's 100 connections, open as they need.

#246: the page reports list_shown, the ms from asking for a list to drawing it, with the view
and filter, under the click's trace; background refreshes are not timed. Timings skip report()'s
once-a-minute limit, which is for errors in a loop. A dashboard panel and table, and the prod
check, read it.

#245: the load test's browse scenario subscribes by OPML and leaves the Directory, which is
ipx-directory's since #204, to it.

CLAUDE.md records the owner's leave to EXPLAIN (ANALYZE, BUFFERS) any query on production,
read only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/load/run.js

@@ -189,7 +189,8 @@ async function seed() {
   }
   // The media test's listener takes the feeds with files. They may be downloaded already: the
   // first start subscribes the admin to the whole catalogue, so the first scan fetched them.
-  for (let n = 0; n < MEDIA; n++) await api('listener', `/api/popular/${feedId(n)}`, { method: 'POST' });
+  // By OPML as the others: /api/popular asks the directory, which this harness does not start (#245).
+  await api('listener', '/api/opml', { method: 'POST', body: JSON.stringify({ xml: opml(Array.from({ length: MEDIA }, (_, n) => n)) }) });
   for (let t = Date.now(); ; await new Promise(r => setTimeout(r, 500))) {
     const got = await api('listener', '/api/entries?filter=downloaded&limit=50');
     if (got.entries.flatMap(e => e.enclosures).filter(x => x.path).length >= MEDIA) break;