Add gateway-connect UI and per-app internet-exposure toggle

Settings page gets a "Furtka Gateway" section: connect (gateway URL +
registration token + box name, polls /api/gateway/connect/status the same
way the update-apply flow polls /update-state.json) and disconnect, plus
a status readout (gateway URL, tunnel state). Removed "Remote access"
from the "Coming next" list now that it exists.

The Apps page's installed-app rows get an "Expose to Internet" control,
shown only when the manifest declares internet.viable — fetched lazily
per app (loadInternetSlots()) since the publish state isn't part of the
main /api/apps listing. Toggling calls the existing
GET/POST /api/apps/<name>/internet endpoints; the subdomain prompt uses a
plain window.prompt() rather than extending the settings modal, since
this needs a live network round-trip and a returned public URL that the
generic settings form has no way to express.

Verified end-to-end in a real browser against a running furtka serve +
a stub gateway server (login, publish, unpublish, connect-with-missing-
systemd-run, disconnect, and the client-side required-field validation),
not just by reading the generated HTML/JS.

assets/www/settings/index.html

@@ -80,6 +80,45 @@
             </div>
         </section>
 
+        <section>
+            <h2>Furtka Gateway</h2>
+            <div class="card">
+                <p class="lede">
+                    Connect this box to a furtka-gateway to expose individual apps to the
+                    internet over a WireGuard tunnel. Apps stay private until you explicitly
+                    publish one from the <a href="/apps">Apps</a> page — connecting here only
+                    opens the tunnel, nothing is exposed automatically.
+                </p>
+                <div id="gateway-disconnected">
+                    <div class="field">
+                        <label for="gw-url">Gateway URL</label>
+                        <input type="text" id="gw-url" placeholder="https://gw.example.com">
+                    </div>
+                    <div class="field">
+                        <label for="gw-token">Registration token</label>
+                        <input type="password" id="gw-token" placeholder="from the gateway operator">
+                    </div>
+                    <div class="field">
+                        <label for="gw-name">Box name</label>
+                        <input type="text" id="gw-name" placeholder="my-box">
+                    </div>
+                    <div class="update-actions">
+                        <button id="gateway-connect-btn">Connect</button>
+                    </div>
+                </div>
+                <div id="gateway-connected" hidden>
+                    <dl class="kv">
+                        <dt>Gateway</dt><dd id="gw-connected-url">—</dd>
+                        <dt>Tunnel</dt><dd id="gw-tunnel-status">—</dd>
+                    </dl>
+                    <div class="update-actions">
+                        <button class="danger" id="gateway-disconnect-btn">Disconnect</button>
+                    </div>
+                </div>
+                <p id="gateway-status" class="hint"></p>
+            </div>
+        </section>
+
         <section>
             <h2>Appearance</h2>
             <div class="card">
@@ -112,7 +151,6 @@
                 <a href="https://furtka.org/#planned">Change hostname</a>
                 <a href="https://furtka.org/#planned">Backup</a>
                 <a href="https://furtka.org/#planned">User accounts</a>
-                <a href="https://furtka.org/#planned">Remote access</a>
             </div>
         </section>
 
@@ -339,6 +377,120 @@
             await refreshHttpsStatus();
         })();
 
+        // --- Furtka Gateway -------------------------------------------------
+
+        const CONNECT_STAGE_LABELS = {
+            registering: 'Registering with the gateway…',
+            starting_tunnel: 'Starting the WireGuard tunnel…',
+            done: 'Connected.',
+        };
+
+        const gatewayDisconnectedEl = document.getElementById('gateway-disconnected');
+        const gatewayConnectedEl = document.getElementById('gateway-connected');
+        const gwConnectedUrlEl = document.getElementById('gw-connected-url');
+        const gwTunnelStatusEl = document.getElementById('gw-tunnel-status');
+        const gatewayStatusEl = document.getElementById('gateway-status');
+        const gatewayConnectBtn = document.getElementById('gateway-connect-btn');
+        const gatewayDisconnectBtn = document.getElementById('gateway-disconnect-btn');
+        let gatewayPollHandle = null;
+
+        function setGatewayStatus(msg, isError = false) {
+            gatewayStatusEl.textContent = msg;
+            gatewayStatusEl.style.color = isError ? 'var(--danger)' : 'var(--muted)';
+        }
+
+        function describeTunnel(tunnel) {
+            if (!tunnel || !tunnel.configured) return 'not configured';
+            return tunnel.latest_handshake ? `up (last handshake ${tunnel.latest_handshake})` : 'configured, no handshake yet';
+        }
+
+        async function refreshGatewayStatus() {
+            try {
+                const r = await fetch('/api/gateway/status', { cache: 'no-store' });
+                if (!r.ok) return;
+                const s = await r.json();
+                gatewayDisconnectedEl.hidden = !!s.connected;
+                gatewayConnectedEl.hidden = !s.connected;
+                if (s.connected) {
+                    gwConnectedUrlEl.textContent = s.gateway_url;
+                    gwTunnelStatusEl.textContent = describeTunnel(s.tunnel);
+                }
+            } catch (e) {
+                /* next refresh will retry */
+            }
+        }
+        refreshGatewayStatus();
+
+        gatewayConnectBtn.addEventListener('click', async () => {
+            const gateway_url = document.getElementById('gw-url').value.trim();
+            const registration_token = document.getElementById('gw-token').value;
+            const box_name = document.getElementById('gw-name').value.trim();
+            if (!gateway_url || !registration_token || !box_name) {
+                setGatewayStatus('Gateway URL, registration token, and box name are all required.', true);
+                return;
+            }
+            gatewayConnectBtn.disabled = true;
+            setGatewayStatus('Connecting…');
+            try {
+                const r = await fetch('/api/gateway/connect', {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify({ gateway_url, registration_token, box_name }),
+                });
+                const data = await r.json();
+                if (!r.ok) {
+                    setGatewayStatus(data.error || `HTTP ${r.status}`, true);
+                    gatewayConnectBtn.disabled = false;
+                    return;
+                }
+                gatewayPollHandle = setInterval(pollGatewayConnectState, 2000);
+            } catch (e) {
+                setGatewayStatus(`Network error: ${e.message}`, true);
+                gatewayConnectBtn.disabled = false;
+            }
+        });
+
+        async function pollGatewayConnectState() {
+            try {
+                const r = await fetch('/api/gateway/connect/status', { cache: 'no-store' });
+                if (!r.ok) return;
+                const s = await r.json();
+                const label = CONNECT_STAGE_LABELS[s.stage] || `Stage: ${s.stage}`;
+                setGatewayStatus(label, s.stage === 'error');
+                if (s.stage === 'done') {
+                    clearInterval(gatewayPollHandle);
+                    gatewayConnectBtn.disabled = false;
+                    await refreshGatewayStatus();
+                } else if (s.stage === 'error') {
+                    clearInterval(gatewayPollHandle);
+                    gatewayConnectBtn.disabled = false;
+                    if (s.error) setGatewayStatus(`${label} — ${s.error}`, true);
+                }
+            } catch (e) {
+                /* keep polling; transient blip expected */
+            }
+        }
+
+        gatewayDisconnectBtn.addEventListener('click', async () => {
+            if (!confirm('Disconnect from the gateway? Any apps currently exposed to the internet will stop being reachable.')) return;
+            gatewayDisconnectBtn.disabled = true;
+            setGatewayStatus('Disconnecting…');
+            try {
+                const r = await fetch('/api/gateway/disconnect', { method: 'POST' });
+                const data = await r.json();
+                if (!r.ok) {
+                    setGatewayStatus(data.error || `HTTP ${r.status}`, true);
+                    return;
+                }
+                setGatewayStatus('Disconnected.');
+                await refreshGatewayStatus();
+            } catch (e) {
+                setGatewayStatus(`Network error: ${e.message}`, true);
+            } finally {
+                gatewayDisconnectBtn.disabled = false;
+            }
+        });
+
         async function pollUpdateState() {
             try {
                 const r = await fetch('/update-state.json', { cache: 'no-store' });

furtka/api.py

@@ -358,6 +358,12 @@ async function refresh() {
         const openBtn = openHref
           ? `<a class="btn" href="${esc(openHref)}" target="_blank" rel="noopener">Open</a>`
           : '';
+        // Filled in async by loadInternetSlots() after this markup lands —
+        // the toggle's current state needs its own fetch per app
+        // (/api/apps/<name>/internet), so it can't be known at row-build time.
+        const internetSlot = (a.internet && a.internet.viable)
+          ? `<span class="internet-slot" data-name="${esc(a.name)}"></span>`
+          : '';
         return `
       <div class="app">
         <div class="left">
@@ -369,6 +375,7 @@ async function refresh() {
         </div>
         <div class="buttons">
           ${openBtn}
+          ${internetSlot}
           ${hasSettings ? `<button data-op="edit" data-name="${esc(a.name)}">Settings</button>` : ''}
           <button class="secondary" data-op="update" data-name="${esc(a.name)}">Update</button>
           <button class="secondary" data-op="reinstall" data-name="${esc(a.name)}">Reinstall</button>
@@ -393,6 +400,65 @@ async function refresh() {
   for (const btn of document.querySelectorAll('button[data-op]')) {
     btn.addEventListener('click', () => handleButton(btn.dataset.op, btn.dataset.name, btn));
   }
+  loadInternetSlots();
+}
+
+// Populates each installed internet-viable app's "Expose to Internet" /
+// "Public …" control. Separate from the main refresh() render because the
+// current publish state needs its own per-app fetch — the /api/apps list
+// only carries whether an app is *capable* of being exposed, not whether
+// it currently is.
+async function loadInternetSlots() {
+  for (const slot of document.querySelectorAll('.internet-slot')) {
+    const name = slot.dataset.name;
+    try {
+      const r = await fetch(`/api/apps/${encodeURIComponent(name)}/internet`);
+      if (!r.ok) continue;
+      renderInternetSlot(slot, name, await r.json());
+    } catch (e) {
+      // Leave the slot empty — next refresh() retries.
+    }
+  }
+}
+
+function renderInternetSlot(slot, name, data) {
+  if (data.enabled) {
+    slot.innerHTML =
+      `<a class="btn" href="${esc(data.public_url)}" target="_blank" rel="noopener">Public ↗</a>` +
+      `<button class="secondary" data-internet="${esc(name)}">Stop exposing</button>`;
+  } else {
+    slot.innerHTML = `<button class="secondary" data-internet="${esc(name)}">Expose to Internet</button>`;
+  }
+  slot.querySelector('[data-internet]').addEventListener('click', () => handleInternetToggle(name, !!data.enabled));
+}
+
+async function handleInternetToggle(name, currentlyEnabled) {
+  const logEl = document.getElementById('log');
+  if (currentlyEnabled) {
+    if (!confirm(`Stop exposing ${name} to the internet?`)) return;
+  }
+  let subdomain = null;
+  if (!currentlyEnabled) {
+    subdomain = prompt(
+      `Public hostname for ${name} — needs its own DNS record already pointing at your gateway:`
+    );
+    if (!subdomain) return;
+  }
+  try {
+    const r = await fetch(`/api/apps/${encodeURIComponent(name)}/internet`, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify(currentlyEnabled ? { enabled: false } : { enabled: true, subdomain }),
+    });
+    const data = await r.json();
+    if (!r.ok) {
+      logEl.textContent = `[internet ${name}] HTTP ${r.status}\\n` + JSON.stringify(data, null, 2);
+      return;
+    }
+    await refresh();
+  } catch (e) {
+    logEl.textContent = `[internet ${name}] Network error: ${e.message}`;
+  }
 }
 
 async function handleButton(op, name, btn) {