Add ability to end a run as victory or defeat

Add End Run button to run dashboard with a confirmation modal offering
Victory/Defeat choice. Backend auto-sets completedAt timestamp and
validates only active runs can be ended. Ended runs show a completion
banner with date and duration, rename team to "Final Team", and hide
encounter logging and status change interactions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/hooks/useRuns.ts

@@ -1,4 +1,5 @@
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { toast } from 'sonner'
 import { getRuns, getRun, createRun, updateRun, deleteRun } from '../api/runs'
 import type { CreateRunInput, UpdateRunInput } from '../types/game'
 
@@ -30,9 +31,14 @@ export function useUpdateRun(id: number) {
   const queryClient = useQueryClient()
   return useMutation({
     mutationFn: (data: UpdateRunInput) => updateRun(id, data),
-    onSuccess: () => {
+    onSuccess: (_result, data) => {
       queryClient.invalidateQueries({ queryKey: ['runs'] })
+      queryClient.invalidateQueries({ queryKey: ['runs', id] })
+      if (data.status === 'completed') toast.success('Run marked as completed!')
+      else if (data.status === 'failed') toast.success('Run marked as failed')
+      else toast.success('Run updated')
     },
+    onError: (err) => toast.error(`Failed to update run: ${err.message}`),
   })
 }