Add the Browser tab: a live web page with no browser chrome

A new tab (globe, after Maps) shows one web page full-bleed in the content area —
no address bar, bookmarks or scrollbars — built for It Is Written but usable with
any page. It loads at startup and keeps running in the background.

Stage (browser-tab.js, browser-guest-preload.cjs):
- An Electron <webview> per Browser tab, in its own sandboxed process and persistent
  session. The pages live in one persistent layer inside .tab-content: every tab
  switch rebuilds .tab-content and moving a webview reloads it, so app.js now clears
  around that layer (clearTabContentKeepingBrowser).
- Tapping a text field brings up the Prayer tab's keyboard (createPrayerKeyboard with
  a sink) and types into the page with trusted input; Enter submits; the keyboard puts
  itself away when the page moves focus on (e.g. after a search). The OS touch
  keyboard is suppressed with inputmode="none" while a field is focused.
- Tapping a scripture reference opens it in a new Bible tab, in the translation
  printed beside it when that one is switched on. References are found with the app's
  own scanner: scripture-scan.js gains scanAll() (every match with its offsets),
  translationAfter() and isTranslation(); scanText/parseSlide are unchanged.
- Input inside a webview never reaches the app, so the page reports activity (idle
  splash) and five-finger touches (blank the screen) itself.
- main.cjs: webviewTag on; every webview is forced sandboxed, context-isolated, no Node,
  http(s) only, with the guest preload. No new windows (opened in place), no permission
  prompts, no downloads, no pinch-zoom, no alert/confirm/prompt boxes, and "Leave
  site?" can never block Reload or Start page. The session reports plain Chrome.
- server.js CSP: frame-src allows http(s) (a webview is a frame to CSP); style-src and
  font-src allow https (the follower's srcdoc copy inherits this policy).

Everywhere a tab kind is listed:
- app.js: create at startup and on Reset, icon, visibility defaults, + menu, fixed
  mode, no ink layer, tool handling, OSC kind + information line (the page's search
  term), phone remote scroll / tap / page buttons, OSC show / reload / home actions,
  live setting changes, translation for tapped references.
- quick-dock, tool-wheel, presentation-tools: no drawing tools on the tab.
- Phone remote: tab label, one finger scrolls the page (taps still tap), hint text;
  mirror-stream.js reports the page's scroll for the phone's local preview.
- Follower screen: the stage publishes a script-free copy of the page's DOM (only while
  a follower is linked), its scroll and form fields; the follower shows it in
  sandboxed, double-buffered frames; the relay keeps the page for late joiners.
- OSC: /bibleapp/browser, /bibleapp/browser/reload, /bibleapp/browser/home;
  tab_kind/browser feedback. Admin and phone allow-lists updated.
- Settings: Tab Visibility, a Browser Tab section (start page, page size, scripture
  taps, return to start page), Service Profiles carry its settings, OSC references.
- Admin console: show the tab, reload / start page, start page and page size.
- BROWSER_TAB.md documents it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

settings.html

@@ -829,7 +829,7 @@
                     <div style="color:#777; margin-bottom:14px; font-size:13px; line-height:1.9;">
                         <code style="color:#8cc88c;">/bibleapp/feedback/state/tab_active/&lt;n&gt;</code> &mdash; <code>1</code> while the <strong>n-th tab on the row</strong> is showing (1&ndash;16).<br>
                         <code style="color:#8cc88c;">/bibleapp/feedback/state/tab_kind/&lt;kind&gt;</code> &mdash; <code>1</code> while a tab of that <strong>kind</strong> is showing:<br>
-                        <span style="margin-left:18px;">bible &middot; sync &middot; whiteboard &middot; notes &middot; media &middot; alpha &middot; announcements &middot; graphics &middot; maps &middot; prayer &middot; ask</span>
+                        <span style="margin-left:18px;">bible &middot; sync &middot; whiteboard &middot; notes &middot; media &middot; alpha &middot; announcements &middot; graphics &middot; maps &middot; browser &middot; prayer &middot; ask</span>
                     </div>
                     <label style="display:flex; align-items:center; gap:8px; margin:0;">
                         <input type="checkbox" id="oscFeedbackTabStates"> Send per-tab on/off states for Companion button colours
@@ -943,6 +943,57 @@
             </div>
         </div>
         
+        <!-- Browser Tab Settings -->
+        <div class="section">
+            <h2>Browser Tab</h2>
+            <p style="color: #999; margin-bottom: 18px;">
+                The Browser tab shows one web page, full screen in the tab: no address bar, bookmarks or scrollbars.
+                It loads when the app starts and keeps running while other tabs are showing, so it is ready the moment
+                you open it. Scroll it with a finger; tap a text box on the page and the app's own keyboard comes up to
+                type into it; tap a scripture reference on the page to open it in a new Bible tab. The booth follower
+                screen shows the same page, clean.
+            </p>
+            <div class="form-group">
+                <label for="browserTabUrl">Start page</label>
+                <input type="url" id="browserTabUrl" placeholder="https://it-is-written-waters-church.vercel.app/" onchange="saveBrowserTabSettings()"
+                       style="width: 100%; max-width: 560px; padding: 10px; background: #1f1f1f; color: #e0e0e0; border: 1px solid #444; border-radius: 6px;">
+                <div class="help-text">The page the tab opens. Leave blank for It Is Written. Changing it takes the tab to the new page.</div>
+            </div>
+            <div class="form-group">
+                <label for="browserTabZoom">Page size</label>
+                <select id="browserTabZoom" onchange="saveBrowserTabSettings()"
+                        style="width: 100%; max-width: 360px; padding: 10px; background: #1f1f1f; color: #e0e0e0; border: 1px solid #444; border-radius: 6px;">
+                    <option value="auto">Auto — fit the page to the screen</option>
+                    <option value="75">75%</option>
+                    <option value="100">100%</option>
+                    <option value="125">125%</option>
+                    <option value="150">150%</option>
+                    <option value="175">175%</option>
+                    <option value="200">200%</option>
+                    <option value="250">250%</option>
+                    <option value="300">300%</option>
+                </select>
+                <div class="help-text">Auto lays the page out like a tablet and scales it to fill the width — on the portrait TV that is
+                    about 200%. Pick a size if a site looks too small or too big.</div>
+            </div>
+            <div class="form-group">
+                <label style="display:flex; align-items:center; gap:8px;">
+                    <input type="checkbox" id="browserTabScriptureTaps" onchange="saveBrowserTabSettings()"> Tap a scripture reference on the page to open it in a new Bible tab
+                </label>
+                <div class="help-text">Opens in the translation printed beside the reference (e.g. NIV) when that translation is switched on
+                    here, otherwise in the default. Taps anywhere else work on the page as normal.</div>
+            </div>
+            <div style="display:flex; gap:10px; flex-wrap:wrap; align-items:center;">
+                <span style="color:#8cc88c; font-size:13px;">✓ Saves automatically</span>
+                <button type="button" class="btn btn-secondary" onclick="browserTabBackToStart()">Return to the start page</button>
+            </div>
+            <div class="help-text" style="margin-top:8px;">
+                The tab remembers where it was (a search, how far down) while the app is running, so a trip to Settings does
+                not lose it. <strong>Return to the start page</strong> clears that, as does the refresh button on the TV.
+                From the booth: OSC <code>/bibleapp/browser/home</code> and <code>/bibleapp/browser/reload</code>.
+            </div>
+        </div>
+
         <!-- Ask Tab (AI) Settings -->
         <div class="section">
             <h2>Ask Tab (AI Assistant)</h2>
@@ -1002,6 +1053,14 @@
                     <div><strong>/bibleapp/close</strong> - Close active tab</div>
                     <div><strong>/bibleapp/tab/left</strong> - Switch to previous tab</div>
                     <div><strong>/bibleapp/tab/right</strong> - Switch to next tab</div>
+                    <div><strong>/bibleapp/maps</strong> - Show the Maps &amp; Timelines tab</div>
+                    <div><strong>/bibleapp/browser</strong> - Show the Browser tab</div>
+                </div>
+
+                <div style="margin-bottom: 10px;"><strong style="color: #4a9eff;">Browser tab:</strong></div>
+                <div style="margin-left: 10px; margin-bottom: 10px;">
+                    <div><strong>/bibleapp/browser/reload</strong> - Reload the page (if it hung or looks wrong)</div>
+                    <div><strong>/bibleapp/browser/home</strong> - Take the page back to its start page (Settings › Browser Tab)</div>
                 </div>
 
                 <div style="margin-bottom: 10px;"><strong style="color: #4a9eff;">Tools:</strong></div>
@@ -2027,6 +2086,7 @@
             { mode: 'announcements', label: 'Announcements Tab', description: 'Image-based announcements display' },
             { mode: 'graphics', label: 'Graphics Tab', description: 'Image-based graphics display' },
             { mode: 'maps', label: 'Maps & Timelines Tab', description: 'Image gallery for maps and timelines' },
+            { mode: 'browser', label: 'Browser Tab', description: 'A live web page, full screen in the tab with no browser bars (set it up under Browser Tab below)' },
             { mode: 'whiteboard', label: 'Whiteboard Tab', description: 'Blank whiteboard for drawing' },
             { mode: 'notes', label: 'Notes Tab', description: 'PDF notes with annotations' },
             { mode: 'prayer', label: 'Prayer Tab', description: 'Text editor for prayers and notes' },
@@ -2791,6 +2851,43 @@
             }).join('<br>');
         }
         try { if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', loadSplashTriggers); else loadSplashTriggers(); } catch (_) {}
+
+        // ---- Browser Tab (browser-tab.js reads these from the same-origin localStorage) ----
+        const BROWSER_TAB_DEFAULT_URL = 'https://it-is-written-waters-church.vercel.app/';
+        function loadBrowserTabSettings() {
+            try {
+                document.getElementById('browserTabUrl').value = localStorage.getItem('browserTabUrl') || '';
+                const z = localStorage.getItem('browserTabZoom') || 'auto';
+                const sel = document.getElementById('browserTabZoom');
+                sel.value = Array.from(sel.options).some(o => o.value === z) ? z : 'auto';
+                document.getElementById('browserTabScriptureTaps').checked = localStorage.getItem('browserTabScriptureTaps') !== '0';
+            } catch (_) {}
+        }
+        function saveBrowserTabSettings() {
+            try {
+                const urlEl = document.getElementById('browserTabUrl');
+                let url = String(urlEl.value || '').trim();
+                // "example.org/page" is what people type; the tab needs a full web address.
+                if (url && !/^https?:\/\//i.test(url)) url = 'https://' + url.replace(/^\/+/, '');
+                if (url) {
+                    try { new URL(url); } catch (_) { showStatus('That start page is not a web address.', 'error'); return; }
+                }
+                const before = localStorage.getItem('browserTabUrl') || '';
+                if (url) localStorage.setItem('browserTabUrl', url); else localStorage.removeItem('browserTabUrl');
+                urlEl.value = url;
+                // A new start page means the tab should go there, not back to where it was on the old one.
+                if (url !== before) { try { sessionStorage.removeItem('browserTabSession'); } catch (_) {} }
+                localStorage.setItem('browserTabZoom', document.getElementById('browserTabZoom').value || 'auto');
+                localStorage.setItem('browserTabScriptureTaps', document.getElementById('browserTabScriptureTaps').checked ? '1' : '0');
+                showStatus('Browser tab saved — ' + (url || BROWSER_TAB_DEFAULT_URL), 'success');
+            } catch (e) { showStatus('Could not save Browser tab settings: ' + e.message, 'error'); }
+        }
+        // Settings replaces the app in this same window, so the session the tab keeps is visible from here.
+        function browserTabBackToStart() {
+            try { sessionStorage.removeItem('browserTabSession'); } catch (_) {}
+            showStatus('The Browser tab will open its start page when you go back to the app.', 'success');
+        }
+        try { if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', loadBrowserTabSettings); else loadBrowserTabSettings(); } catch (_) {}
         window.addEventListener('storage', (ev) => { try { if (ev && ev.key === 'splashHistory') renderSplashHistory(); } catch (_) {} });
 
         // ---- Follower screen (booth mirror → ProPresenter / ATEM) ----
@@ -3058,7 +3155,8 @@
                      'redLetterEnabled', 'redLetterOverrides', 'popupVisibility',
                      'translationVisibility', 'wordPopupsEnabled', 'spotlightHalfPx',
                      'userLaserColor', 'toolWheelEnabled', 'toolWheelStyle', 'toolSnapBackSec',
-                     'idleSplashSeconds', 'fiveFingerSplash', 'ppsyncSeparateAnnotations'].forEach(function (k) {
+                     'idleSplashSeconds', 'fiveFingerSplash', 'ppsyncSeparateAnnotations',
+                     'browserTabUrl', 'browserTabZoom', 'browserTabScriptureTaps'].forEach(function (k) {
                         var v = localStorage.getItem(k);
                         if (v !== null) settings[k] = v;
                     });