CLAUDE: Fix TypeScript error in DefensiveSetup - use on_first/on_second/on_third

Fixed property access bug introduced in previous commit:

**Issue**:
- DefensiveSetup.vue was accessing `gameState.runners.third` and `runners.first/second/third`
- GameState type doesn't have a `runners` property
- Caused TypeScript error: "Property 'runners' does not exist on type 'GameState'"

**Fix**:
- Changed to use correct properties: `on_first`, `on_second`, `on_third`
- Updated infieldDepthOptions: `props.gameState?.on_third` (line 163)
- Updated outfieldDepthOptions: destructure `on_first, on_second, on_third` (line 178)
- Updated hasRunners check: `on_first || on_second || on_third` (line 184)

**Why**:
GameState uses individual nullable properties for runners, not a nested object.
This matches the backend Pydantic model structure.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend-sba/components/Decisions/DefensiveSetup.vue

@@ -160,7 +160,7 @@ const infieldDepthOptions = computed<ButtonGroupOption[]>(() => {
   ]
 
   // Only show infield_in and corners_in if runner on third
-  if (props.gameState?.runners?.third) {
+  if (props.gameState?.on_third) {
     options.push({ value: 'infield_in', label: 'Infield In', icon: '⬆️' })
     options.push({ value: 'corners_in', label: 'Corners In', icon: '◀️▶️' })
   }
@@ -175,13 +175,13 @@ const outfieldDepthOptions = computed<ButtonGroupOption[]>(() => {
 
   // Check for walk-off scenario
   if (props.gameState) {
-    const { inning, half, home_score, away_score, runners } = props.gameState
+    const { inning, half, home_score, away_score, on_first, on_second, on_third } = props.gameState
     const isHomeBatting = half === 'bottom'
     const isLateInning = inning >= 9
     const isCloseGame = isHomeBatting
       ? home_score <= away_score
       : away_score <= home_score
-    const hasRunners = runners?.first || runners?.second || runners?.third
+    const hasRunners = on_first || on_second || on_third
 
     // Only show shallow in walk-off situations
     if (isHomeBatting && isLateInning && isCloseGame && hasRunners) {