style(fe): centralize filter input standardization in PageLayout

PageLayout now provides default styles for all filter inputs:
- Height: 34px
- Padding: 0 0.75rem
- Line-height: 34px
- Border-radius: 4px
- Box-sizing: border-box

This eliminates the need for each page to redefine input styles.
Individual pages now only override width constraints (search-input max-width).

Aligns with DRY principle - single source of truth for input styling.

DataQualityPage:
- Added scoped styles for search-input max-width (350px)

Future: Consider extracting filter inputs into dedicated components
(<KsFilterInput>, <KsFilterSelect>) for even better reusability.

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

frontend/src/features/data-quality/pages/DataQualityPage.vue

@@ -140,3 +140,20 @@ const handleRetry = () => {
   </BatchOperationsPageV2>
 </template>
 
+<style scoped>
+.filters {
+  display: flex;
+  align-items: center;
+  gap: var(--ks-space-3);
+}
+
+.search-input {
+  min-width: 200px;
+  max-width: 350px;
+  width: 100%;
+}
+
+.status-select {
+  min-width: 150px;
+}
+</style>