Add AI Assignment toggle and Tags tab to settings

- Add "Use AI" button to assignments page to switch between algorithmic and GPT-powered suggestions
- Normalize AI suggestions format to match algorithmic format for consistent UI
- Add Tags tab to Settings page with link to expertise tags management
- AI assignment mode shows GPT-analyzed suggestions with confidence scores

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

src/app/(admin)/admin/rounds/[id]/assignments/page.tsx

@@ -76,15 +76,40 @@ function AssignmentManagementContent({ roundId }: { roundId: string }) {
   const [manualDialogOpen, setManualDialogOpen] = useState(false)
   const [selectedJuror, setSelectedJuror] = useState<string>('')
   const [selectedProject, setSelectedProject] = useState<string>('')
+  const [useAI, setUseAI] = useState(false)
 
   const { data: round, isLoading: loadingRound } = trpc.round.get.useQuery({ id: roundId })
   const { data: assignments, isLoading: loadingAssignments } = trpc.assignment.listByRound.useQuery({ roundId })
   const { data: stats, isLoading: loadingStats } = trpc.assignment.getStats.useQuery({ roundId })
-  const { data: suggestions, isLoading: loadingSuggestions, refetch: refetchSuggestions } = trpc.assignment.getSuggestions.useQuery(
+  const { data: isAIAvailable } = trpc.assignment.isAIAvailable.useQuery()
+
+  // Algorithmic suggestions (default)
+  const { data: algorithmicSuggestions, isLoading: loadingAlgorithmic, refetch: refetchAlgorithmic } = trpc.assignment.getSuggestions.useQuery(
     { roundId },
-    { enabled: !!round }
+    { enabled: !!round && !useAI }
   )
 
+  // AI-powered suggestions
+  const { data: aiSuggestionsRaw, isLoading: loadingAI, refetch: refetchAI } = trpc.assignment.getAISuggestions.useQuery(
+    { roundId, useAI: true },
+    { enabled: !!round && useAI }
+  )
+
+  // Normalize AI suggestions to match algorithmic format
+  const aiSuggestions = aiSuggestionsRaw?.suggestions?.map((s) => ({
+    userId: s.jurorId,
+    jurorName: s.jurorName,
+    projectId: s.projectId,
+    projectTitle: s.projectTitle,
+    score: Math.round(s.confidenceScore * 100),
+    reasoning: [s.reasoning],
+  })) ?? []
+
+  // Use the appropriate suggestions based on mode
+  const suggestions = useAI ? aiSuggestions : (algorithmicSuggestions ?? [])
+  const loadingSuggestions = useAI ? loadingAI : loadingAlgorithmic
+  const refetchSuggestions = useAI ? refetchAI : refetchAlgorithmic
+
   // Get available jurors for manual assignment
   const { data: availableJurors } = trpc.user.getJuryMembers.useQuery(
     { roundId },
@@ -111,6 +136,7 @@ function AssignmentManagementContent({ roundId }: { roundId: string }) {
       utils.assignment.listByRound.invalidate({ roundId })
       utils.assignment.getStats.invalidate({ roundId })
       utils.assignment.getSuggestions.invalidate({ roundId })
+      utils.assignment.getAISuggestions.invalidate({ roundId })
       setSelectedSuggestions(new Set())
     },
   })
@@ -438,24 +464,40 @@ function AssignmentManagementContent({ roundId }: { roundId: string }) {
             <div>
               <CardTitle className="text-lg flex items-center gap-2">
                 <Sparkles className="h-5 w-5 text-amber-500" />
-                Smart Assignment Suggestions
+                {useAI ? 'AI Assignment Suggestions' : 'Smart Assignment Suggestions'}
               </CardTitle>
               <CardDescription>
-                AI-powered recommendations based on expertise matching and workload
-                balance
+                {useAI
+                  ? 'GPT-powered recommendations analyzing project descriptions and judge expertise'
+                  : 'Algorithmic recommendations based on tag matching and workload balance'}
               </CardDescription>
             </div>
-            <Button
-              variant="outline"
-              size="sm"
-              onClick={() => refetchSuggestions()}
-              disabled={loadingSuggestions}
-            >
-              <RefreshCw
-                className={`mr-2 h-4 w-4 ${loadingSuggestions ? 'animate-spin' : ''}`}
-              />
-              Refresh
-            </Button>
+            <div className="flex items-center gap-2">
+              <Button
+                variant={useAI ? 'default' : 'outline'}
+                size="sm"
+                onClick={() => {
+                  setUseAI(!useAI)
+                  setSelectedSuggestions(new Set())
+                }}
+                disabled={!isAIAvailable && !useAI}
+                title={!isAIAvailable ? 'OpenAI API key not configured' : undefined}
+              >
+                <Sparkles className={`mr-2 h-4 w-4 ${useAI ? 'text-amber-300' : ''}`} />
+                {useAI ? 'AI Mode' : 'Use AI'}
+              </Button>
+              <Button
+                variant="outline"
+                size="sm"
+                onClick={() => refetchSuggestions()}
+                disabled={loadingSuggestions}
+              >
+                <RefreshCw
+                  className={`mr-2 h-4 w-4 ${loadingSuggestions ? 'animate-spin' : ''}`}
+                />
+                Refresh
+              </Button>
+            </div>
           </div>
         </CardHeader>
         <CardContent>