Fix graph sidebar visibility with overflow visible

- Add overflow: visible to .graph-view to prevent clipping
- Add .content-area.graph-view rule for parent overflow fix

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

deck-frontend/src/styles/main.css

@@ -223,6 +223,7 @@ body {
 
 /* === CONTENT AREA === */
 .content-area { flex: 1; overflow: hidden; position: relative; }
+.content-area.graph-view { overflow: visible; }
 
 /* === GRID VIEW === */
 .grid-view {
@@ -399,6 +400,7 @@ body {
     width: 100%;
     height: 100%;
     position: relative;
+    overflow: visible !important;
 }
 .graph-view svg { width: 100%; height: 100%; display: block; background: var(--bg); }
 .node { cursor: pointer; }