docs(entries): spell out the difference between the reveal eye and the secret lock

Both toggles mask the value, so they read as duplicates. Tooltips now say which one is temporary and which one changes what is stored.

js/app.js

@@ -4260,8 +4260,10 @@ function buildCustomFieldRow(field, idx, rerender) {
     }
 
     // Reveal eye — only meaningful for secret fields.
+    // Two nearby toggles that look alike: the eye is a temporary peek, the lock
+    // changes what is stored. Spell that out — the visible effect overlaps.
     const eye = el('button', { class: 'icon-btn icon-btn-sm', type: 'button',
-                               title: 'Show / hide' });
+                               title: 'Reveal for now (does not change the setting)' });
     eye.appendChild(icon('i-eye'));
     // All button handlers below stopPropagation — see CLAUDE.md
     // "Click-outside-slideover bug" for why.
@@ -4281,7 +4283,9 @@ function buildCustomFieldRow(field, idx, rerender) {
     const secretBtn = el('button', {
         class: 'so-custom-secret-toggle' + (field.is_secret ? ' is-on' : ''),
         type: 'button',
-        title: field.is_secret ? 'Secret field — value hidden' : 'Public field',
+        title: field.is_secret
+            ? 'Stored as secret — masked every time it is opened. Click to make it public.'
+            : 'Public field — shown in clear. Click to store it as a secret.',
     }, field.is_secret ? '🔒' : '👁');
     secretBtn.addEventListener('click', ev => {
         ev.stopPropagation();