style(fe): remove redundant input styles - use PageLayout defaults

Removed duplicate input field styling from individual pages:
- ModelsList.vue: removed .input height/padding/border styles
- ShadowRunQueue.vue: removed .input height/padding/border styles
- ApprovalQueue.vue: removed .filters and .input styles

PageLayout now provides the authoritative source for input styling:
- All inputs in .ks-page__filters use consistent 34px height
- Padding: 0 0.75rem
- Border-radius: 4px
- Box-sizing: border-box

Individual pages now only define width constraints (max-width: 350px for search).

This applies the DRY principle - single source of truth for filter input
styling across all pages. Reduces code duplication and improves
maintainability.

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

frontend/src/features/shadow-run/pages/ShadowRunQueue.vue

@@ -234,20 +234,6 @@ h1 {
   min-width: 150px;
 }
 
-.input {
-  height: 34px;
-  padding: 0 0.75rem;
-  border: var(--border-width-1) solid var(--color-input-border);
-  border-radius: 4px;
-  background: var(--color-input-background);
-  color: var(--color-text-primary);
-  font-size: 13px;
-  font-family: var(--font-sans);
-  line-height: 34px;
-  box-sizing: border-box;
-  transition: all var(--transition-fast);
-}
-
 .input:hover {
   border-color: var(--color-input-hover);
 }