Fix empty Facture/Libellé cells having nothing to click

Facture and libellé rendered their span with no fallback text when
empty, unlike Client's existing "|| '—'" -- an empty span has zero
width/height, so there was nothing there to click at all. Added the
same "—" placeholder to both.

Also switched .figli-editable-cell to display: block with a min-height,
so the clickable area fills the whole cell's content box instead of
just hugging the text -- a lone "—" character was still a tiny target
even with a placeholder.

web/modules/custom/figli_compta_ledger/css/home.css

@@ -327,7 +327,12 @@ html.gin--dark-mode #figli-home-app {
    plain text rather than a pill -- a dotted underline is enough of an
    affordance without implying a fixed set of choices the way the type
    badge's pill shape does. */
+/* display: block + min-height (not just the default inline text-only
+   box) so the whole cell is a forgiving click target even when empty --
+   the "—" placeholder alone is a tiny, easy-to-miss target otherwise. */
 #figli-home-app .figli-editable-cell {
+  display: block;
+  min-height: 1.2em;
   cursor: pointer;
   border-bottom: 1px dotted transparent;
 }