Code pages describe themselves (code, what for, shop, status, expiry, minimum spend, recent reports) instead of the same 'Validity unknown. Expiry unknown.' on every page (#76)

ddiff --git a/server/http/public.js b/server/http/public.js
iindex d2ebaed..7d6bcac 100644
---- a/server/http/public.js
++++ b/server/http/public.js
@@@ -34,6 +34,22 @@ const { SCOPES } = require('../auth/capabilities');
  
  const COUPON_ID_RE = /^cpn_[0-9A-HJKMNP-TV-Z]{26}$/;
  
++/**
++ * A code page's meta description, from the code's own facts and never its submitted description: the code, what it
++ * is for and where, then its status, expiry, minimum spend, new-customer rule and recent reports, kept under 160
++ * characters. It was "Validity unknown. Expiry unknown." on nearly every code page, the same line 156 times.
++ */
++function couponDescription(v, m) {
++    const facts = [pages.STATUS_LABEL[v.status], v.expiry.known ? `expires ${v.expiry.expires_at.slice(0, 10)}` : 'no expiry stated'];
++    const min = (v.restrictions || []).find((r) => r.kind === 'min_spend');
++    if (min) facts.push(`minimum spend ${min.amount}`);
++    if ((v.restrictions || []).some((r) => r.kind === 'new_customers_only')) facts.push('new customers only');
++    const { worked = 0, failed = 0, window_days: days } = v.reports || {};
++    if (worked || failed) facts.push(`${worked} worked and ${failed} failed in ${days} days`);
++    const text = `Coupon code ${v.code} for ${v.title} at ${m.name}: ${facts.join(', ')}.`;
++    return text.length <= 160 ? text : `${text.slice(0, 159).replace(/\s+\S*$/, '')}…`;
++}
++
  function createPublicRoutes(ctx) {
      const { config, store, merchants, coupons, reports, watches, installs, publication, viewers, moderation, actorLimits } = ctx;
      const router = express.Router();
@@@ -267,7 +283,7 @@ function createPublicRoutes(ctx) {
          const flashMsg = FLASH[req.query.done] || null;
          send(req, res, 200, {
              title: `${v.code} — ${v.title} at ${m.name}`,
--            description: `${pages.STATUS_LABEL[v.status]}. ${v.expiry.known ? `Expires ${v.expiry.expires_at.slice(0, 10)}.` : 'Expiry unknown.'}`,
++            description: couponDescription(v, m),
              decision: publication.couponDecision(c, m), canonical: v.url, jsonLd: jsonLd(m, v),
              body: pages.couponPage({ v, m, history: await coupons.history(c.id), viewer: req.viewer, csrf: csrf(req), back: `/c/${c.id}`, flashMsg }),
          }, { cacheable: !flashMsg });
ddiff --git a/test/pages-discovery.test.js b/test/pages-discovery.test.js
iindex c85934c..4c3ecad 100644
---- a/test/pages-discovery.test.js
++++ b/test/pages-discovery.test.js
@@@ -80,6 +80,10 @@ const { boot, check, done } = require('./helpers/boot');
          const page = (await t.get(`/c/${codeId}`)).text;
          assert.strictEqual((page.match(/<h1\b/g) || []).length, 1, 'the code page has one h1: its title');
          assert.match(page, /<h1 class="coupon-title">/);
++        // Its description is its own facts, not the same "Validity unknown. Expiry unknown." as every other code.
++        const desc = (page.match(/<meta name="description" content="([^"]*)">/) || [])[1] || '';
++        assert.match(desc, /^Coupon code VEG5 for .+ at .+: (Validity unknown|Reported working|Reported not working), (expires \d{4}-\d{2}-\d{2}|no expiry stated)[^"]*\.$/, desc);
++        assert.ok(desc.length <= 160, desc);
          const blocks = [...page.matchAll(/<script type="application\/ld\+json">([\s\S]*?)<\/script>/g)].map((m) => JSON.parse(m[1]));
          assert.deepStrictEqual(blocks.map((b) => b['@type']).sort(), ['BreadcrumbList', 'WebPage']);
          const json = (await t.get(`/c/${codeId}.json`)).json();