feat(vapi-webhook): track subscription usage when calls end

- Update minutes_used in store_subscriptions after each call
- Log usage details in subscription_usage_log table
- Skip usage tracking for cancelled/expired subscriptions

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

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

supabase/functions/vapi-webhook/index.ts

@@ -204,6 +204,56 @@ serve(async (req) => {
 
     console.log('Call log stored successfully:', data.id)
 
+    // Update subscription usage if call had duration
+    if (message.durationSeconds && message.durationSeconds > 0) {
+      const minutesConsumed = message.durationSeconds / 60
+      console.log(`Updating subscription usage: ${minutesConsumed.toFixed(2)} minutes for store ${storeId}`)
+
+      // Get current subscription
+      const { data: subscription, error: subError } = await supabase
+        .from('store_subscriptions')
+        .select('id, minutes_used, minutes_included, status')
+        .eq('store_id', storeId)
+        .single()
+
+      if (subError || !subscription) {
+        console.error('No subscription found for store:', storeId, subError)
+      } else if (subscription.status === 'cancelled' || subscription.status === 'expired') {
+        console.log('Subscription is not active, skipping usage update:', subscription.status)
+      } else {
+        // Update minutes_used in store_subscriptions
+        const { error: updateError } = await supabase
+          .from('store_subscriptions')
+          .update({
+            minutes_used: (subscription.minutes_used || 0) + minutesConsumed
+          })
+          .eq('id', subscription.id)
+
+        if (updateError) {
+          console.error('Error updating subscription usage:', updateError)
+        } else {
+          console.log(`Subscription usage updated: ${(subscription.minutes_used || 0) + minutesConsumed} total minutes used`)
+
+          // Log usage in subscription_usage_log
+          const { error: logError } = await supabase
+            .from('subscription_usage_log')
+            .insert({
+              subscription_id: subscription.id,
+              store_id: storeId,
+              call_log_id: data.id,
+              minutes_consumed: minutesConsumed,
+              source_type: 'included' // For now, all usage comes from included minutes
+            })
+
+          if (logError) {
+            console.error('Error logging subscription usage:', logError)
+          } else {
+            console.log('Subscription usage logged successfully')
+          }
+        }
+      }
+    }
+
     // Trigger analytics processing (non-blocking)
     const analyticsApiKey = Deno.env.get('ANALYTICS_INTERNAL_API_KEY')
     if (analyticsApiKey && message.transcript) {