fix(clipboard): copy toasts reflect the configured clear delay

The "clears in 30s" suffix was hardcoded in ~14 toasts. Single helper
clipClearSuffix() reads clipboardClearSeconds (''=Never); prefixes concatenated
to it. Cheatsheet text made generic "(auto-clears)".

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

js/app.overlays.js

@@ -152,7 +152,7 @@ async function quickSearchPickEntry(entry, mode) {
         if (!u) { toast('No username on this entry', 'warning'); return; }
         if (Bridge.active) Bridge.copySecure(u, 30000);
         else { try { await navigator.clipboard.writeText(u); } catch (_) {} }
-        toast('Username copied · clears in 30s');
+        toast('Username copied' + clipClearSuffix());
     } else {
         const pwd = await decryptPwd(entry.encrypted_password, entry.iv);
         if (pwd === '[ERROR]') { toast('Decryption error', 'error'); return; }
@@ -202,7 +202,7 @@ const CHEATSHEET_GROUPS = [
         title: 'On each card',
         items: [
             { keys: [{ icon: 'i-globe' }], desc: 'Open the site in your default browser' },
-            { keys: [{ icon: 'i-copy' }],  desc: 'Copy password to the secure clipboard (auto-clears in 30s)' },
+            { keys: [{ icon: 'i-copy' }],  desc: 'Copy password to the secure clipboard (auto-clears)' },
             { keys: ['Click card'],         desc: 'Open the entry details / edit panel' },
         ],
     },
@@ -306,7 +306,7 @@ async function openHistoryModal(entryId) {
         copy.addEventListener('click', () => {
             if (Bridge.active) Bridge.copySecure(plain, 30000);
             else { try { navigator.clipboard.writeText(plain); } catch (_) {} }
-            toast('Copied · clears in 30s');
+            toast('Copied' + clipClearSuffix());
         });
         preview.appendChild(copy);