feat: configurable STUN server fallbacks for WebRTC ICE

The WebRTC transport relied on a single Google STUN server — if it was
unreachable, ICE gathering waited the full 4s timeout. Now four public
servers are used by default (Google ×2, Cloudflare, Mozilla), configurable
via node.toml, the Node page UI, and the CLI (meshbay-node stun list|add|
remove|reset). Changes are hot-swapped on the live transport.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/node-page.js b/packages/meshbay-hub/src/meshbay_hub/static/node-page.js
index 9a6db7d..87a9815 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/node-page.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/node-page.js
@@ -102,6 +102,9 @@ export function NodePage({ groups }) {
   const [nodeSettings, setNodeSettings] = useState(null);
   const [editSettings, setEditSettings] = useState(null);
   const [savingSettings, setSavingSettings] = useState(false);
+  const [editStun, setEditStun] = useState(null);
+  const [savingStun, setSavingStun] = useState(false);
+  const [stunInput, setStunInput] = useState('');
   const [operatorPaired, setOperatorPaired] = useState(false);
   const [pairBusy, setPairBusy] = useState(false);
   const [pairStatus, setPairStatus] = useState('');
@@ -131,6 +134,7 @@ export function NodePage({ groups }) {
 
   useEffect(() => {
     if (nodeSettings && !editSettings) setEditSettings({ ...nodeSettings });
+    if (nodeSettings && !editStun) setEditStun([...(nodeSettings.stun_servers || [])]);
   }, [nodeSettings]);
 
   const refresh = useCallback(async () => {
@@ -291,6 +295,61 @@ export function NodePage({ groups }) {
     }
   }, [editSettings]);
 
+  const saveStun = useCallback(async () => {
+    if (!editStun) return;
+    setSavingStun(true);
+    setActionMsg('');
+    try {
+      await nodeCall('PUT', '/api/node-settings', { stun_servers: editStun });
+      setNodeSettings(s => s ? { ...s, stun_servers: [...editStun] } : s);
+      setActionMsg(t('node.stun_saved'));
+    } catch (err) {
+      setActionMsg(platform.bridgeMessage(err));
+    } finally {
+      setSavingStun(false);
+    }
+  }, [editStun]);
+
+  const addStunServer = useCallback(() => {
+    const url = stunInput.trim();
+    if (!url) return;
+    if (!url.startsWith('stun:')) {
+      setActionMsg(t('node.stun_invalid'));
+      return;
+    }
+    if (editStun && editStun.includes(url)) {
+      setActionMsg(t('node.stun_duplicate'));
+      return;
+    }
+    setEditStun(s => [...(s || []), url]);
+    setStunInput('');
+    setActionMsg('');
+  }, [stunInput, editStun]);
+
+  const removeStunServer = useCallback((idx) => {
+    setEditStun(s => s.filter((_, i) => i !== idx));
+  }, []);
+
+  const moveStunServer = useCallback((idx, dir) => {
+    setEditStun(s => {
+      const a = [...s];
+      const target = idx + dir;
+      if (target < 0 || target >= a.length) return a;
+      [a[idx], a[target]] = [a[target], a[idx]];
+      return a;
+    });
+  }, []);
+
+  const resetStunDefaults = useCallback(() => {
+    setEditStun([
+      'stun:stun.l.google.com:19302',
+      'stun:stun1.l.google.com:19302',
+      'stun:stun.cloudflare.com:3478',
+      'stun:stun.services.mozilla.com:3478',
+    ]);
+    setActionMsg('');
+  }, []);
+
   const doPairOperator = useCallback(async () => {
     setPairBusy(true);
     setPairStatus('');
@@ -559,6 +618,51 @@ export function NodePage({ groups }) {
           </div>
         </div>
       `}
+
+      ${editStun && html`
+        <div class="node-group">
+          <span class="settings-heading">${t('node.stun_servers')}</span>
+          <p class="node-hint">${t('node.stun_hint')}</p>
+          ${editStun.length === 0 ? html`
+            <p class="node-hint">${t('node.stun_empty')}</p>
+          ` : html`
+            <div class="stun-server-list">
+              ${editStun.map((url, idx) => html`
+                <div class="stun-server-entry" key=${url + idx}>
+                  <span class="stun-server-url">${url}</span>
+                  <div class="stun-server-actions">
+                    <button class="btn btn-small btn-icon" disabled=${idx === 0}
+                      onClick=${() => moveStunServer(idx, -1)}
+                      title=${t('node.stun_move_up')}>▲</button>
+                    <button class="btn btn-small btn-icon" disabled=${idx === editStun.length - 1}
+                      onClick=${() => moveStunServer(idx, 1)}
+                      title=${t('node.stun_move_down')}>▼</button>
+                    <button class="btn btn-small btn-danger btn-icon"
+                      onClick=${() => removeStunServer(idx)}
+                      title=${t('node.stun_remove')}>✕</button>
+                  </div>
+                </div>
+              `)}
+            </div>
+          `}
+          <div class="stun-add-row">
+            <input type="text" placeholder=${t('node.stun_add_placeholder')}
+              value=${stunInput}
+              onInput=${e => setStunInput(e.target.value)}
+              onKeyDown=${e => { if (e.key === 'Enter') addStunServer(); }} />
+            <button class="btn btn-small btn-secondary" onClick=${addStunServer}>
+              ${t('node.stun_add')}</button>
+          </div>
+          <div class="node-settings-actions">
+            <button class="btn btn-primary btn-small" disabled=${savingStun || busy}
+              onClick=${saveStun}>
+              ${savingStun ? t('node.stun_saving') : t('node.stun_save')}</button>
+            <button class="btn btn-small btn-secondary" disabled=${savingStun || busy}
+              onClick=${resetStunDefaults}>
+              ${t('node.stun_reset')}</button>
+          </div>
+        </div>
+      `}
     </div>
   `;
 }