fix(fe): enforce grid height to fill available viewport space

ISSUE: Grid height was constrained to min-height: 220px, leaving large
unused space on page (3 rows visible, lots of empty area below).

PRINCIPLE: Grid must expand to fill available vertical space in viewport.

CHANGES:
ModelOperationTable.vue (.grid-wrapper)
- Removed: min-height: 220px (artificial constraint)
- Added: height: 100%
- Added: min-height: 0 (critical for flex overflow behavior)

RESULT: Grid now spans full available height in flex container,
utilizing screen space efficiently.

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

frontend/src/features/model-operations/components/ModelOperationTable.vue

@@ -63,7 +63,8 @@ const columns: UiGridColumn[] = [
 .grid-wrapper {
   width: 100%;
   flex: 1;
-  min-height: 220px;
+  height: 100%;
+  min-height: 0;
   border: 1px solid var(--ks-color-border);
   border-radius: var(--ks-radius-sm);
   overflow: hidden;