feat: add AIAssistPanel with replace and merge modes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/network/panels/AIAssistPanel.tsx

@@ -0,0 +1,131 @@
+import { useState, useCallback } from 'react'
+import { Sparkles, ChevronUp, ChevronDown, AlertTriangle } from 'lucide-react'
+import { cn } from '@/lib/utils'
+import { networkDiagramsApi } from '@/api'
+import type { AIGenerateResponse } from '@/types'
+
+interface AIAssistPanelProps {
+  onGenerate: (result: AIGenerateResponse, mode: 'replace' | 'merge') => void
+  getExistingBounds: () => { minX: number; maxX: number; minY: number; maxY: number } | null
+  hasNodes: boolean
+}
+
+export function AIAssistPanel({ onGenerate, getExistingBounds, hasNodes }: AIAssistPanelProps) {
+  const [expanded, setExpanded] = useState(false)
+  const [description, setDescription] = useState('')
+  const [mode, setMode] = useState<'replace' | 'merge'>('replace')
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  const handleGenerate = useCallback(async () => {
+    if (!description.trim()) return
+    setLoading(true)
+    setError(null)
+    try {
+      const result = await networkDiagramsApi.aiGenerate({
+        description: description.trim(),
+        mode,
+        existingBounds: mode === 'merge' ? getExistingBounds() : null,
+      })
+      onGenerate(result, mode)
+      setDescription('')
+      setExpanded(false)
+    } catch (err: unknown) {
+      const msg = err instanceof Error ? err.message : 'Generation failed. Please try again.'
+      setError(msg)
+    } finally {
+      setLoading(false)
+    }
+  }, [description, mode, onGenerate, getExistingBounds])
+
+  if (!expanded) {
+    return (
+      <div className="border-t border-default bg-card">
+        <button
+          onClick={() => setExpanded(true)}
+          className="flex w-full items-center justify-center gap-2 px-4 py-2 text-xs text-muted-foreground hover:text-primary"
+        >
+          <Sparkles size={14} />
+          AI Generate
+          <ChevronUp size={14} />
+        </button>
+      </div>
+    )
+  }
+
+  return (
+    <div className="border-t border-default bg-card">
+      <div className="flex items-center justify-between border-b border-default px-4 py-2">
+        <div className="flex items-center gap-2 text-xs font-medium text-heading">
+          <Sparkles size={14} />
+          AI Generate
+        </div>
+        <button onClick={() => setExpanded(false)} className="text-muted-foreground hover:text-primary">
+          <ChevronDown size={14} />
+        </button>
+      </div>
+
+      <div className="flex flex-col gap-3 p-4">
+        <div className="flex gap-2">
+          <button
+            onClick={() => setMode('replace')}
+            className={cn(
+              'rounded px-3 py-1 text-xs font-medium transition-colors',
+              mode === 'replace'
+                ? 'bg-accent text-white'
+                : 'border border-default text-muted-foreground hover:text-primary',
+            )}
+          >
+            Generate New
+          </button>
+          <button
+            onClick={() => setMode('merge')}
+            className={cn(
+              'rounded px-3 py-1 text-xs font-medium transition-colors',
+              mode === 'merge'
+                ? 'bg-accent text-white'
+                : 'border border-default text-muted-foreground hover:text-primary',
+            )}
+          >
+            Add to Diagram
+          </button>
+        </div>
+
+        {mode === 'replace' && hasNodes && (
+          <div className="flex items-start gap-2 rounded border border-yellow-500/30 bg-yellow-500/5 px-3 py-2">
+            <AlertTriangle size={14} className="mt-0.5 shrink-0 text-yellow-400" />
+            <p className="text-[11px] text-yellow-400">
+              This will replace your current diagram. Save first if needed.
+            </p>
+          </div>
+        )}
+
+        <textarea
+          value={description}
+          onChange={e => setDescription(e.target.value)}
+          placeholder="Describe the network you want to create... e.g. 'Small office with a firewall, core switch, 3 access points, and a file server'"
+          rows={3}
+          disabled={loading}
+          className="w-full resize-none rounded border border-default bg-input px-3 py-2 text-xs text-primary placeholder:text-muted-foreground focus:border-accent focus:outline-none disabled:opacity-50"
+        />
+
+        {error && <p className="text-[11px] text-red-400">{error}</p>}
+
+        {loading ? (
+          <div className="flex items-center justify-center gap-2 py-2">
+            <div className="h-2 w-2 animate-pulse rounded-full bg-accent" />
+            <span className="text-xs text-muted-foreground">Generating your network diagram...</span>
+          </div>
+        ) : (
+          <button
+            onClick={handleGenerate}
+            disabled={!description.trim()}
+            className="rounded bg-accent px-4 py-2 text-xs font-medium text-white hover:bg-accent/90 disabled:opacity-50"
+          >
+            Generate
+          </button>
+        )}
+      </div>
+    </div>
+  )
+}