#14 draft: guarantee the save at leave-time (fixes switch-chats-and-return loss)

Per-keystroke 'input' saves can be missed on mobile (predictive text or a fast
tap-away fires no final input event), which lost the whole draft when you switched
chats and came back. Added persistCurrentDraft() — snapshots the composer value
into the current chat's draft key the instant you leave it (selectChat before the
swap, and showWelcome/back). Restore on open was already correct. Skipped while
editing.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/public/home.html

@@ -3420,6 +3420,11 @@ let _openUnread=0; // set by selectChat (the unread count before it's reset) so
 function draftKey(kind,id){ return 'draft_'+((ME&&ME.id)||'')+'_'+kind+':'+id; }
 function getDraft(kind,id){ try{ return localStorage.getItem(draftKey(kind,id))||''; }catch(_){ return ''; } }
 function setDraft(kind,id,val){ try{ if(val&&val.trim()) localStorage.setItem(draftKey(kind,id), val); else localStorage.removeItem(draftKey(kind,id)); }catch(_){} }
+// #14: GUARANTEED save of the currently-open chat's draft — called the instant we leave it (switching chats
+// OR going back to the list). The per-keystroke 'input' save can be missed on mobile (predictive text / a
+// fast tap-away fires no final input event), which lost the whole draft on switch-and-return. Snapshotting
+// the composer value at leave-time makes it reliable regardless. Skipped while editing (that's not a draft).
+function persistCurrentDraft(){ try{ if(selected && !editTarget){ const inp=document.getElementById('msgInput'); if(inp) setDraft(selected.kind, selected.id, inp.value); } }catch(_){} }
 // Compositor-only open slide (workflow-verified). armOpenSlide() runs AFTER openConvo's synchronous
 // render: it pins the pane off-screen (chat-opening), lets a frame paint it, then adds .chat-anim on a
 // double-rAF so the compositor runs the 300ms transform with the main thread idle. All scrollTop/innerHTML
@@ -3810,6 +3815,7 @@ function openPollModal(gid){
 }
 async function selectChat(kind,id){
   ensureNotifyPermission();
+  persistCurrentDraft();      // #14: snapshot the outgoing chat's draft BEFORE we swap (reliable across the switch)
   stopTyping();               // leaving the previous conversation → tell that peer we stopped
   if(_selMode) exitSelect();  // #1: leave forward-selection when changing chats
   selected={kind,id};
@@ -6045,6 +6051,7 @@ function switchTab(tab){
   if(tab==='meeting' && meetState==='idle'){ renderMeetingLobby(); }
 }
 function showWelcome(skipAnim){
+  persistCurrentDraft(); // #14: save the open chat's draft before we leave it for the list (back button)
   const finish=()=>{ selected=null; document.body.classList.remove('chat-open','chat-closing','chat-dragging'); renderChats(searchVal()); renderChatPanel(); updateRailUnread(); };
   // Mobile: slide the outgoing conversation off to the right before swapping back to the chat list, so
   // "back" has a clear push/pop direction (like Teams/WhatsApp). Desktop just closes instantly.