Improve Set-Struktur editor: show parent set inline, clamp long descriptions

Removes the per-row indentation (span.ind) in favor of a small "belongs to
set" tag shown above each row's title, so membership is visible without
tracing indentation depth even while sets are expanded. Description text
is now clamped to 2 lines with ellipsis by default and expands to a
scrollable ~12-line view on click.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Fuchs/js/intranet/modules/fis.inv_shared.scss

@@ -588,8 +588,23 @@
 				span.fold { cursor: pointer; margin-right: 0.35rem; color: #555; display: inline-block; width: 1rem; }
 			}
 			td.ttl {
-				span.ind { display: inline-block; }
-				span.seti { margin-right: 0.3rem; color: #888; }
+				span.seti {
+					display: block;
+					margin-bottom: 0.15rem;
+					color: #888;
+					font-size: 0.75rem;
+					&::before { content: '\21B3\0020'; }
+				}
+				span.txt {
+					display: -webkit-box;
+					-webkit-box-orient: vertical;
+					-webkit-line-clamp: 2;
+					overflow: hidden;
+					white-space: normal;
+					line-height: 1.3rem;
+					cursor: pointer;
+					&.exp { -webkit-line-clamp: unset; display: block; max-height: 15.6rem; overflow-y: auto; }
+				}
 				span.cnt { color: #999; font-weight: normal; font-size: 0.85rem; }
 			}
 			td.act { width: 7.5rem; white-space: nowrap; text-align: right;