SEO-13: each dated row on the public schedule is an Event node (#5)

ddiff --git a/server/http/pages.js b/server/http/pages.js
iindex 9f50276..7300608 100644
---- a/server/http/pages.js
++++ b/server/http/pages.js
@@@ -30,6 +30,15 @@ const DAY = 24 * 60 * 60_000;
  /** One event's end: its own, or an hour after it starts. */
  const eventEnd = (e) => e.ends_at || new Date(new Date(e.starts_at).getTime() + 60 * 60_000).toISOString();
  
++/**
++ * The page's JSON-LD in one script: every node in one @graph, so a page carries exactly one JSON-LD script.
++ * The nodes keep their own fields; only their own @context goes, because the graph carries it once.
++ */
++const oneGraph = (nodes) => {
++    const graph = nodes.filter(Boolean).map((n) => { const c = { ...n }; delete c['@context']; return c; });
++    return [{ '@context': 'https://schema.org', '@graph': graph }];
++};
++
  /** schema.org Event for one of this site's events. */
  function eventJsonLd(e, config) {
      const base = String(config.baseUrl).replace(/\/+$/, '');
@@@ -69,7 +78,8 @@ function createPublicPageViews(ctx) {
              title: null,
              body: raw(views.home({ upcoming: rows, now })),
              description: 'Streams, events and reminders across OpenVibe on one calendar: schedule a stream, get reminded, and subscribe in your own calendar app.',
--            jsonLd: homeJsonLd(config),
++            // Every row on the page is a dated, public event the reader can open: that is exactly one Event node.
++            jsonLd: oneGraph([...homeJsonLd(config), ...rows.map((e) => eventJsonLd(e, config)), seo.jsonLd.organization()]),
          };
      }
  
ddiff --git a/test/discovery.test.js b/test/discovery.test.js
iindex 7fb73c6..df4d43b 100644
---- a/test/discovery.test.js
++++ b/test/discovery.test.js
@@@ -61,7 +61,10 @@ const PRIVATE = ['/auth/', '/api/', '/me', '/brief', '/schedule', '/internal'];
  
          await check('home page: WebSite, WebApplication and WebPage JSON-LD', async () => {
              const r = await t.get('/');
--            const blocks = [...r.text.matchAll(/<script type="application\/ld\+json">([\s\S]*?)<\/script>/g)].map((m) => JSON.parse(m[1]));
++            // One JSON-LD script per page: every node lives in the page's @graph.
++            const scripts = [...r.text.matchAll(/<script type="application\/ld\+json">([\s\S]*?)<\/script>/g)].map((m) => JSON.parse(m[1]));
++            assert.strictEqual(scripts.length, 1, 'the page carries exactly one JSON-LD script');
++            const blocks = scripts.flatMap((x) => (Array.isArray(x['@graph']) ? x['@graph'] : [x]));
              const types = blocks.map((b) => b['@type']);
              assert.ok(types.includes('WebSite'), types.join(','));
              assert.ok(types.includes('WebApplication'), types.join(','));
ddiff --git a/test/pages.test.js b/test/pages.test.js
iindex ce5b80e..bf2f564 100644
---- a/test/pages.test.js
++++ b/test/pages.test.js
@@@ -7,9 +7,13 @@ const assert = require('assert');
  const { boot, check, done } = require('./helpers/boot');
  const { assetVersion } = require('../server/render/layout');
  
--function jsonLd(html) {
++// One JSON-LD script per page: every node lives in the page's @graph.
++function scripts(html) {
      return [...String(html).matchAll(/<script type="application\/ld\+json">([\s\S]*?)<\/script>/g)].map((m) => JSON.parse(m[1]));
  }
++function jsonLd(html) {
++    return scripts(html).flatMap((x) => (Array.isArray(x['@graph']) ? x['@graph'] : [x]));
++}
  
  (async () => {
      const t = await boot();
@@@ -26,9 +30,21 @@ function jsonLd(html) {
          assert.strictEqual(r.headers.get('cache-control'), 'public, max-age=60');
          assert.strictEqual(r.headers.get('vary'), 'Cookie');
          for (const marker of ['id="td-home"', 'id="td-upcoming"', 'id="main"', '<noscript><nav', '<footer id="ov-footer"', 'Public stream']) assert.ok(r.text.includes(marker), marker);
++        assert.strictEqual(scripts(r.text).length, 1, 'the page carries exactly one JSON-LD script');
          const types = jsonLd(r.text).map((x) => x['@type']);
          assert.ok(types.includes('WebSite'), types.join(','));
          assert.ok(types.includes('WebApplication'), types.join(','));
++        // The day's list is dated, so each row is an Event node describing the event it links to.
++        const events = jsonLd(r.text).filter((x) => x['@type'] === 'Event');
++        assert.strictEqual(events.length, 1, 'one Event for the one event on the page');
++        assert.strictEqual(events[0].name, 'Public stream');
++        assert.strictEqual(events[0].startDate, event.starts_at);
++        assert.strictEqual(events[0].url, `https://openvibe.today/e/${event.id}`);
++        assert.strictEqual(events[0].organizer.name, '@alice');
++        assert.ok(r.text.includes(`href="/e/${event.id}"`), "the Event's url is the row's link");
++        // A page with nothing dated says so by having no Event node.
++        const developers = jsonLd((await t.get('/developers')).text);
++        assert.ok(!developers.some((x) => x['@type'] === 'Event'));
      });
  
      await check('a page drawn for a signed-in person is private, no-store', async () => {