fix(entries): size the multiline field from its content instead of a fixed height

A manual resize was lost on reopen: the row is rebuilt on every open, and remembering the height would not survive a restart either since localStorage is wiped when the ephemeral port changes the origin. Deriving it from the content removes the state entirely - the field is always the right size.

TEST_SCENARIOS.md

@@ -78,7 +78,7 @@ Préparer : 3 entrées `A`, `B`, `C`, dont `A` dans le dossier `Work` avec le ta
 
 ### A12 · pas de fausse alerte (non-régression d'A11)
 Aucun de ces enchaînements ne doit afficher « Entry changed elsewhere » :
-- **A12a** : `A` ouverte + dirty → Save → modifier encore → Save (le rechargement post-save re-cale la référence)
+- **A12a** : `A` ouverte + dirty → Save → modifier encore → Save (le rechargement post-save re-cale la référence)✅
 - **A12b** : `A` ouverte + dirty → batch *Add tag* / *Move to folder* sur `A` → Save (l'éditeur a absorbé le changement)
 - **A12c** : `A` ouverte + dirty → supprimer son dossier → Save (cf. A7)
 - **A12d** : `A` ouverte + dirty → *Fetch missing* favicons → Save (l'icône est hors payload éditeur)

css/style.css

@@ -1604,11 +1604,12 @@ input[type="range"]::-webkit-slider-thumb {
 /* Multiline custom field (Notes). The row stays a grid, so the textarea just
    grows in its own column and the buttons keep their places. */
 .so-custom-multiline {
-    min-height: 72px;
+    min-height: 56px;
     resize: vertical;
     align-self: stretch;
     font-family: inherit;
     line-height: 1.5;
+    overflow-y: auto;   /* JS caps the auto-grow; past that it scrolls */
 }
 /* Editable combobox for option-backed custom fields (card brand, expiry
    year…). Input fills the cell; the arrow drops a menu of ALL options. */

js/app.js

@@ -4161,6 +4161,12 @@ function soCustomFieldsField() {
     return wrap;
 }
 
+// Grow a textarea to fit its content, up to a cap past which it scrolls.
+function autoSizeTextarea(ta, maxPx = 320) {
+    ta.style.height = 'auto';
+    ta.style.height = Math.min(ta.scrollHeight, maxPx) + 'px';
+}
+
 function buildCustomFieldRow(field, idx, rerender) {
     const row = el('div', { class: 'so-custom-row' });
     const labelInput = el('input', {
@@ -4189,10 +4195,18 @@ function buildCustomFieldRow(field, idx, rerender) {
     if (field.multiline) {
         valueInput = el('textarea', {
             class: 'so-input so-custom-value so-custom-multiline',
-            rows: 5, placeholder: 'Value',
+            rows: 3, placeholder: 'Value',
             autocomplete: 'off', autocorrect: 'off', spellcheck: 'false',
         });
         valueInput.classList.toggle('is-masked', !!field.is_secret);
+        // Height follows the content instead of being remembered: a manual
+        // resize would be lost anyway (re-rendered on every open, and
+        // localStorage is wiped each launch when the port changes).
+        const grow = () => autoSizeTextarea(valueInput);
+        valueInput.addEventListener('input', grow);
+        // scrollHeight reads 0 until the element is in the DOM — same
+        // render-time vs DOM-attachment trap as renderSoChips (CLAUDE.md).
+        setTimeout(grow, 0);
     } else {
         valueInput = el('input', {
             type: field.is_secret ? 'password' : 'text',