Agent layer: /.well-known/agent.json and Markdown twins of the public pages (#119)

ddiff --git a/server/agent-descriptor.js b/server/agent-descriptor.js
nnew file mode 100644
iindex 0000000..5e50fc1
---- /dev/null
++++ b/server/agent-descriptor.js
@@@ -0,0 +1,16 @@
++'use strict';
++// What openvibe.tips tells an agent about itself (openvibe-shared/agent-layer): /.well-known/agent.json.
++// Every field is something this site really serves: the JSON API, the llms.txt/sitemap machine map, and
++// the auth that API accepts (service client-credentials tokens and Network user tokens). No OpenAPI
++// document or documentation page is published, so neither is named.
++module.exports = {
++    id: 'tips',
++    name: 'OpenVibe.Tips',
++    purpose: 'Creator support on the OpenVibe network: tips, goals, paid messages, text-to-speech and media requests, sounds and stream overlays, with money moved by OpenVibe.Billing.',
++    home: 'https://openvibe.tips',
++    site: 'openvibe.tips',
++    api: '/api/v1',
++    policy: {
++        auth: ['none', 'Network OIDC', 'service token'],
++    },
++};
ddiff --git a/server/agent-pages.js b/server/agent-pages.js
nnew file mode 100644
iindex 0000000..e069324
---- /dev/null
++++ b/server/agent-pages.js
@@@ -0,0 +1,91 @@
++'use strict';
++// The Markdown twins of openvibe.tips' public pages (openvibe-shared/agent-layer), rendered by the same
++// data readers and page builders the routes use (web/pages.js through web/layout.js), signed out so a
++// twin can never carry a viewer's tip form or a creator's private preview. Private pages (dashboard,
++// receipts, moderation, overlays, auth, API) are never rendered here; a creator page that is switched
++// off has no twin.
++const crypto = require('crypto');
++const { sql } = require('openvibe-sdk/db');
++const frame = require('openvibe-shared/frame');
++const ovServe = require('openvibe-shared/serve');
++const pages = require('./web/pages');
++
++const HOME_DESCRIPTION = 'Tip the creators you watch: paid messages, text-to-speech, media requests and sounds, with goals and alert overlays for OBS on any streaming app.';
++
++function createAgentPages({ domain, config, layout, liveNow = { list: async () => [] } }) {
++    const { profiles, goals, interactions, sounds, db } = domain;
++    const twin = (o) => ({ html: layout.page({ ...o, viewer: null }) });
++
++    async function home() {
++        const [rows, live] = await Promise.all([
++            db.many(sql`SELECT creator_subject, handle, display_name, avatar_url, headline FROM creator_tip_profiles WHERE page_enabled ORDER BY updated_at DESC LIMIT 24`),
++            liveNow.list(),
++        ]);
++        const creators = await Promise.all(rows.map(async (p) => {
++            const [goal] = await goals.presentMany(db, (await goals.list(db, p.creator_subject, { status: 'active' })).slice(0, 1));
++            return { handle: p.handle, display_name: p.display_name, avatar_url: p.avatar_url, headline: p.headline, goal: goal ? { title: goal.title, percent: goal.percent } : null };
++        }));
++        return twin({
++            active: 'home', canonicalPath: '/', title: 'Tips, paid messages and stream alerts', description: HOME_DESCRIPTION,
++            styles: [require('openvibe-shared/showcase').STYLESHEET], wide: true, body: pages.home({ creators, live }),
++        });
++    }
++
++    function updates() {
++        return twin({ canonicalPath: '/updates', title: 'What shipped on OpenVibe.Tips', body: frame.updatesBody({ service: 'tips', siteName: 'OpenVibe.Tips' }) + `<script src="${ovServe.url('shipped.js')}" defer></script>` });
++    }
++
++    async function creator(handle) {
++        const p = await profiles.byHandle(db, handle);
++        if (!p || !p.page_enabled) return null;
++        const list = await goals.publicGoals(db, await goals.list(db, p.creator_subject), p);
++        const publicSounds = p.sounds_enabled ? await sounds.list(db, p.creator_subject) : [];
++        return twin({
++            title: `Support ${p.display_name}`, active: 'creator', canonicalPath: `/${p.handle}`,
++            description: p.headline || `Tip ${p.display_name} on OpenVibe.Tips: tips, goals, paid messages${p.tts_enabled ? ', text-to-speech' : ''}${p.media_requests_enabled ? ', media requests' : ''}.`,
++            robots: 'index,follow', ogImage: p.avatar_url || undefined,
++            body: pages.creatorPage({
++                profile: p, goals: list, viewer: null, csrf: '', idem: `agent-${crypto.randomBytes(12).toString('base64url')}`,
++                values: {}, providers: config.billing.providers, error: null, ownerPreview: false, sounds: publicSounds,
++            }),
++        });
++    }
++
++    async function creatorGoals(handle) {
++        const p = await profiles.byHandle(db, handle);
++        if (!p || !p.page_enabled) return null;
++        return twin({
++            title: `${p.display_name} — goals`, canonicalPath: `/${p.handle}/goals`, robots: 'index,follow',
++            body: pages.goalsPage({ profile: p, goals: await goals.publicGoals(db, await goals.list(db, p.creator_subject), p) }),
++        });
++    }
++
++    async function creatorSupporters(handle) {
++        const p = await profiles.byHandle(db, handle);
++        if (!p || !p.page_enabled || !p.page.supporters_page) return null;
++        const [top, recentRows] = await Promise.all([interactions.leaderboard(db, p), p.page.supporters_messages ? interactions.recentPublic(db, p) : null]);
++        const leaderboard = top.map((row) => (p.page.supporters_amounts ? row : { ...row, total: null }));
++        const recent = recentRows ? recentRows.map((v) => (p.page.supporters_amounts ? v : { ...v, amount: null })) : null;
++        return twin({
++            title: `${p.display_name} — supporters`, canonicalPath: `/${p.handle}/supporters`, robots: 'index,follow',
++            body: pages.supportersPage({ profile: p, leaderboard, recent }),
++        });
++    }
++
++    async function renderPublicPage(path) {
++        const p = String(path || '/').replace(/\/+$/, '') || '/';
++        if (p === '/') return home();
++        if (p === '/updates') return updates();
++        const m = /^\/([^/]+)(\/goals|\/supporters)?$/.exec(p);
++        if (!m) return null;
++        const handle = profiles.normalizeHandle(m[1]);
++        if (!handle) return null;
++        if (m[2] === '/goals') return creatorGoals(handle);
++        if (m[2] === '/supporters') return creatorSupporters(handle);
++        return creator(handle);
++    }
++
++    return { renderPublicPage };
++}
++
++module.exports = { createAgentPages };
ddiff --git a/server/app.js b/server/app.js
iindex c100186..9124969 100644
---- a/server/app.js
++++ b/server/app.js
@@@ -139,7 +139,22 @@ function createApp(opts = {}) {
          },
      }));
      const liveNow = opts.liveNow || require('./clients/live-now').createLiveNow({ config, fetchImpl: opts.fetchImpl, log });
--    app.use(createWebRoutes({ domain, config, layout, userAuth, liveNow }));
++    // The agent layer (openvibe-shared/agent-layer): /.well-known/agent.json and the Markdown twins of the
++    // public pages (server/agent-pages.js). The pages keep their own routes — a signed-in viewer's tip form,
++    // account bar and anti-forgery token are theirs — so only the manifest and twin requests reach this
++    // mount; the pages advertise the twin themselves (web/layout.js and web/routes.js).
++    const webRoutes = createWebRoutes({ domain, config, layout, userAuth, liveNow });
++    const agentLayer = express();
++    require('openvibe-shared/agent-layer').mount(agentLayer, {
++        descriptor: require('./agent-descriptor'),
++        render: require('./agent-pages').createAgentPages({ domain, config, layout, liveNow }).renderPublicPage,
++    });
++    app.use((req, res, next) => {
++        const twin = req.path.endsWith('.md') || (req.query && req.query.format === 'markdown') || String(req.headers.accept || '').includes('text/markdown');
++        if (req.path !== '/.well-known/agent.json' && !twin) return next();
++        return agentLayer(req, res, next);
++    });
++    app.use(webRoutes);
  
      app.use((req, res) => {
          if (req.path.startsWith('/api/') || req.path.startsWith('/internal/')) return http.sendProblem(res, 404, 'not_found', { ctx: req.ov });
ddiff --git a/server/web/layout.js b/server/web/layout.js
iindex 89f6bb9..bdde95f 100644
---- a/server/web/layout.js
++++ b/server/web/layout.js
@@@ -65,6 +65,11 @@ function createLayout({ config, release }) {
              notificationsRealtime: true,   // the bell hears new notifications over OpenVibe.Events (Shared 1.22.0)
          };
          const footer = { service: 'tips', variant: 'auto', path: o.canonicalPath, mount: '#ov-footer', brandName: SITE_NAME, updates: '/updates' };   // full on the front page only (Shared 4.19)
++        // Every indexable page has a Markdown twin (server/agent-pages.js) and names it in the head. A page
++        // rendered for a signed-in person (noindex) never advertises one.
++        const agentHead = o.canonicalPath && !String(robots).includes('noindex')
++            ? require('openvibe-shared/agent-layer').linkHeaderTags(canonical, `${String(config.baseUrl).replace(/\/+$/, '')}/llms.txt`).head
++            : '';
          const who = o.viewer
              ? `<span class="who">Signed in as <b>${esc(o.viewer.name || o.viewer.username || 'you')}</b> · <a href="/auth/logout?next=/">Sign out</a></span>`
              : `<a class="who" href="/auth/login?next=${encodeURIComponent(o.canonicalPath || '/')}">Sign in</a>`;
@@@ -79,6 +84,7 @@ function createLayout({ config, release }) {
              navbar: nav, footer, home: '/', navLinks: NAV_LINKS,
              head: [
                  '<meta name="referrer" content="strict-origin-when-cross-origin">',
++                agentHead,
                  appIcon.headTags({ site: 'tips' }),
                  release ? release.metaTag() : '',
                  `<link rel="stylesheet" href="${asset('css/tips.css')}">`,
ddiff --git a/server/web/routes.js b/server/web/routes.js
iindex c7046ea..20ef1a9 100644
---- a/server/web/routes.js
++++ b/server/web/routes.js
@@@ -60,7 +60,14 @@ function createWebRoutes({ domain, config, layout, userAuth, liveNow = { list: a
      const secret = config.formSecret || crypto.randomBytes(32).toString('hex');
  
      const html = (res, body, status = 200, extraHeaders = {}) => res.status(status).set({ 'Content-Type': 'text/html; charset=utf-8', 'Cache-Control': 'no-cache', ...extraHeaders }).send(body);
--    const pageFor = (req, o) => layout.page({ viewer: req.viewer, ...o });
++    const pageFor = (req, o) => {
++        // A public page names its Markdown twin in the Link header, exactly as the agent layer's own
++        // responses do; a page rendered for a signed-in person (noindex) has no twin and no header.
++        if (o && o.canonicalPath && !String(o.robots || 'index,follow').includes('noindex')) {
++            req.res.set('Link', require('openvibe-shared/agent-layer').linkHeaderTags(layout.abs(o.canonicalPath), `${String(config.baseUrl).replace(/\/+$/, '')}/llms.txt`).header);
++        }
++        return layout.page({ viewer: req.viewer, ...o });
++    };
      const notFound = (req, res) => html(res, pageFor(req, { title: 'Not found', robots: 'noindex', body: pages.errorPage({ status: 404, title: 'Nothing here', message: 'That page does not exist, or its creator has not switched it on.' }) }), 404);
  
      // Anti-forgery for signed-in forms: HMAC(subject, day), valid today and yesterday.