DeadAir in the page: a switch per show, one beside the speed, and the time saved (#172)

A DeadAir switch in each show's settings, and the same switch beside
the speed for the show that is playing, drawn as a waveform with its gap
closed up, outlined when off and solid when on, with aria-pressed. A
file the server gives a copy for plays from /media/{id}/deadair. An
episode's line says how much shorter it is, and Settings says how much
DeadAir has saved you.

Turning it on or off mid-episode saves the place with a request it waits
for, not a beacon, then asks for the entry again from the new
GET /api/entries/{feed}/{guid}, whose position is in the clock of the
version it now plays, and carries on there. A copy not made yet plays
from the next time. Turning a show on wakes the copy maker, so the copy
is there in seconds rather than at its next pass.

The browser test plays a real MP3 with long silences, quiet.mp3, from a
show it adds and removes itself.

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

web/src/dialogs.ts

@@ -363,7 +363,15 @@ function due(ts){
 /// Your settings: the theme, your subscriptions as OPML, and, to read, what the server does
 /// with feeds. The server's own settings, the accounts and the log are on /admin, which only an
 /// admin is sent (issue #19); this used to hold them too, shown to admins only.
+function deadSavedText(me){
+  const s=me&&me.deadair_saved||0;
+  return s?`It has saved you ${spanText(s)}, on episodes you heard three quarters of or more.`
+    :'Turn it on in a show\'s settings, or beside the speed while it plays, to shorten its long silences.';
+}
+
 async function prefsModal(){
+  // Fresh, so the time saved counts what was heard since the page loaded.
+  api('/api/me').then(u=>{ S.me=u; const h=$('#sdeadsaved'); if(h) h.textContent=deadSavedText(u); }).catch(()=>{});
   const g = await api('/api/settings');
   const admin = !!(S.me&&S.me.admin);
   openModal(`<button class="iconbtn cardx" onclick="closeModal()" title="Close" aria-label="Close">${ICON.close}</button><h3>Settings</h3>
@@ -374,6 +382,8 @@ async function prefsModal(){
       <select id="smode">${Object.entries(MODES).map(([k,t])=>
         `<option value="${k}"${theme.mode===k?' selected':''}>${esc(t)}</option>`).join('')}</select>
       <span class="hint">Auto follows your system's light/dark setting.</span></div>
+    <div class="field"><label>DeadAir</label>
+      <span class="hint" id="sdeadsaved">${deadSavedText(S.me)}</span></div>
     <div class="field"><label>Subscriptions</label>
       <div class="inline">
         <!-- Words as well as icons: a floppy disk and a plus mean nothing on their own here. -->
@@ -517,6 +527,9 @@ function settingsModal(f, newUrl?: string){
         <p class="cap">Any one of these will do, and a phrase needs all its words. Empty takes everything.</p></div>
       ${sw(`<input type="checkbox" role="switch" id="sexp"${f.allow_explicit?' checked':''}>`,'Include explicit items')}
     </div></div></div></div>
+    <div class="ffield">${sw(`<input type="checkbox" role="switch" id="sdead"${f.deadair?' checked':''}>`,'DeadAir',' lead')}
+      <p class="cap">Plays ${isGroup?'these shows':'this show'} with long silences shortened, so episodes finish
+      sooner without sounding sped up. Leave it off for readings whose pauses matter.</p></div>
     ${isGroup?'':`<div class="ffield"><label class="flabel" for="sblockin">Hide items that mention</label>
       <div class="chips" id="sblock">${chipsHTML(f.blocked||[],'sblockin')}</div>
       <p class="cap">Whole words or phrases. Hidden from your list and not downloaded for you, along
@@ -600,7 +613,7 @@ function settingsModal(f, newUrl?: string){
       const patch: Record<string, unknown>={
         keywords:chipWords($('#skw')),
         max_new_per_check:mode==='default'?null:mode==='all'?0:newest,
-        auto_download:$('#sauto').checked, allow_explicit:$('#sexp').checked};
+        auto_download:$('#sauto').checked, allow_explicit:$('#sexp').checked, deadair:$('#sdead').checked};
       if($('#sblock')) patch.blocked=chipWords($('#sblock'));
       // The address is the same for everyone: an admin's to change, for a feed that moved, and the
       // API refuses it from anyone else. The folder and category are not this dialog's at all.