An offline channel offers an alert when it goes live, through OpenVibe.Watch (#585)

ddiff --git a/public/css/features/channel.css b/public/css/features/channel.css
iindex 8c2090ea..2a500558 100644
---- a/public/css/features/channel.css
++++ b/public/css/features/channel.css
@@@ -1111,6 +1111,11 @@ button.viewer-badge:focus-visible { outline: 2px solid #93c5fd; outline-offset:
  .ch-meta { display: flex; flex-wrap: wrap; gap: 6px 12px; align-items: center; font-size: 0.85rem; }
  /* Each item stays on one line; on a phone the row wraps instead ("22 / followers" and "IRL · / inferred" did). */
  .ch-follower-count { color: var(--text-muted); white-space: nowrap; }
++/* "Get an alert" (OpenVibe.Watch) sits in the same quiet row: a link, not a second button beside Follow. */
++.ch-watch-alert { color: var(--text-muted); text-decoration: none; white-space: nowrap; }
++.ch-watch-alert:hover, .ch-watch-alert:focus-visible { color: var(--accent); }
++.ch-watch-alert[hidden] { display: none; }
++@media (pointer: coarse) { .ch-watch-alert { position: relative; } .ch-watch-alert::after { content: ''; position: absolute; left: -4px; right: -4px; top: -12px; bottom: -12px; } }
  .ch-meta .ch-category-badge { white-space: nowrap; }
  .ch-actions { flex-shrink: 0; }
  
ddiff --git a/public/fragments/channel.html b/public/fragments/channel.html
iindex 4fc09799..25231c41 100644
---- a/public/fragments/channel.html
++++ b/public/fragments/channel.html
@@@ -252,6 +252,7 @@
                      <div class="ch-next" id="ch-next-offline" hidden></div>
                      <div class="ch-meta">
                          <span class="ch-follower-count" id="ch-follower-count-offline">0 followers</span>
++                        <a class="ch-watch-alert" id="ch-watch-offline" href="https://openvibe.watch/" target="_blank" rel="noopener" hidden><i class="fa-solid fa-bell" aria-hidden="true"></i> Get an alert</a>
                          <a class="ch-game-badge" id="ch-game-badge-offline" href="https://openvibe.games/" target="_blank" rel="noopener" hidden></a>
                          <span class="ch-category-badge badge" id="ch-category-badge-offline">Offline</span>
                      </div>
ddiff --git a/public/js/app-channel.js b/public/js/app-channel.js
iindex 260c0adf..a81de18c 100644
---- a/public/js/app-channel.js
++++ b/public/js/app-channel.js
@@@ -947,6 +947,7 @@ async function loadChannelPage(username, managedStreamRef = null, legacySessionI
              if (window.ChannelSocials) ChannelSocials.pills(document.getElementById('ch-socials-offline'), ch.social_links || []);
              _loadNextStream(ch.username);
              document.getElementById('ch-follower-count-offline').textContent = `${ch.follower_count || 0} followers`;
++            _setWatchAlert(document.getElementById('ch-watch-offline'), ch.username);
              _loadGameBadge(ch.username);
              _setCategoryBadge(document.getElementById('ch-category-badge-offline'), ch.ai_category || ch.category || 'Offline', !!ch.ai_category);
              setupFollowBtn(document.getElementById('ch-btn-follow-offline'));
@@@ -3253,6 +3254,21 @@ function _wireAboutDrag() {
      });
  }
  
++/**
++ * "Get an alert" beside the follower count while a channel is offline: OpenVibe.Watch's form, filled in for this
++ * channel going live (the live.stream.started event, nothing polled). It reaches people where Live's own follow cannot:
++ * an email, a webhook, or one of their agents woken up. Not on one's own channel.
++ */
++function _setWatchAlert(a, username) {
++    if (!a) return;
++    const own = !!(typeof currentUser !== 'undefined' && currentUser && currentUser.username === username);
++    if (own || !username) { a.hidden = true; return; }
++    const q = new URLSearchParams({ template: 'event', event: 'live.stream.started', event_filter: username, name: `@${username} goes live` });
++    a.href = `https://openvibe.watch/watches/new?${q}`;
++    a.title = `An alert when @${username} goes live: by email, a webhook or your agent (OpenVibe.Watch)`;
++    a.hidden = false;
++}
++
  // Render a streamer's customizable offline screen into #ch-offline-screen.
  // image/video → served asset; html → sandboxed iframe (no same-origin, so the
  // streamer's markup can't touch viewers' session). Falls back to a tasteful default.
ddiff --git a/test/channel-watch-alert.test.js b/test/channel-watch-alert.test.js
nnew file mode 100644
iindex 00000000..3d838819
---- /dev/null
++++ b/test/channel-watch-alert.test.js
@@@ -0,0 +1,36 @@
++'use strict';
++// "Get an alert" on an offline channel (plan §4, Agents and devices: the gap was an entry point on Live's channel
++// page): OpenVibe.Watch's form, filled in for this channel going live (live.stream.started, nothing polled), so an
++// alert can reach an email, a webhook or an agent. Hidden on one's own channel and until the channel is known.
++const assert = require('assert');
++const fs = require('fs');
++const path = require('path');
++const vm = require('vm');
++
++const ROOT = path.join(__dirname, '..');
++const fragment = fs.readFileSync(path.join(ROOT, 'public/fragments/channel.html'), 'utf8');
++assert.match(fragment, /<a class="ch-watch-alert" id="ch-watch-offline" href="https:\/\/openvibe\.watch\/" target="_blank" rel="noopener" hidden>/, 'the link is in the offline header, hidden until filled');
++
++const src = fs.readFileSync(path.join(ROOT, 'public/js/app-channel.js'), 'utf8');
++const fn = /function _setWatchAlert\(a, username\) \{[\s\S]*?\n\}/.exec(src);
++assert.ok(fn, '_setWatchAlert exists');
++assert.match(src, /_setWatchAlert\(document\.getElementById\('ch-watch-offline'\), ch\.username\);/, 'the offline header fills it');
++
++const run = (viewer, username) => {
++    const a = { hidden: true, href: 'https://openvibe.watch/', title: '' };
++    const ctx = { currentUser: viewer, URLSearchParams };
++    vm.createContext(ctx);
++    vm.runInContext(`${fn[0]}\n_setWatchAlert(a, ${JSON.stringify(username)});`, Object.assign(ctx, { a }));
++    return a;
++};
++
++const a = run({ username: 'someone' }, 'goosely');
++assert.strictEqual(a.hidden, false);
++const u = new URL(a.href);
++assert.strictEqual(u.origin + u.pathname, 'https://openvibe.watch/watches/new');
++assert.deepStrictEqual(Object.fromEntries(u.searchParams), { template: 'event', event: 'live.stream.started', event_filter: 'goosely', name: '@goosely goes live' });
++assert.match(a.title, /@goosely goes live: by email, a webhook or your agent/);
++assert.strictEqual(run(null, 'goosely').hidden, false, 'signed out too: Watch asks them to sign in');
++assert.strictEqual(run({ username: 'goosely' }, 'goosely').hidden, true, 'not on one\'s own channel');
++assert.strictEqual(run(null, '').hidden, true, 'not before the channel is known');
++console.log('channel watch alert: all checks passed');