feat(frontend): convert ExportPreviewModal to editable textarea with reset

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

frontend/src/components/session/ExportPreviewModal.tsx

@@ -1,5 +1,5 @@
-import { useState } from 'react'
-import { Copy, Download, Check } from 'lucide-react'
+import { useState, useEffect } from 'react'
+import { Copy, Download, Check, RotateCcw } from 'lucide-react'
 import { Modal } from '@/components/common/Modal'
 import { cn } from '@/lib/utils'
 
@@ -9,7 +9,9 @@ interface ExportPreviewModalProps {
   content: string
   filename: string
   format: 'markdown' | 'text' | 'html' | 'psa'
-  onDownload: () => void
+  onDownload: (content: string) => void
+  includeSummary?: boolean
+  onToggleSummary?: (include: boolean) => void
 }
 
 export function ExportPreviewModal({
@@ -19,12 +21,20 @@ export function ExportPreviewModal({
   filename,
   format,
   onDownload,
+  includeSummary = false,
+  onToggleSummary,
 }: ExportPreviewModalProps) {
   const [copied, setCopied] = useState(false)
+  const [editedContent, setEditedContent] = useState(content)
+
+  // Sync editedContent when content prop changes (new fetch / summary toggle)
+  useEffect(() => {
+    setEditedContent(content)
+  }, [content])
 
   const handleCopy = async () => {
     try {
-      await navigator.clipboard.writeText(content)
+      await navigator.clipboard.writeText(editedContent)
       setCopied(true)
       setTimeout(() => setCopied(false), 2000)
     } catch (err) {
@@ -33,39 +43,79 @@ export function ExportPreviewModal({
   }
 
   const handleDownload = () => {
-    onDownload()
+    onDownload(editedContent)
     onClose()
   }
 
-  // Reset copied state when modal closes
+  const handleReset = () => {
+    setEditedContent(content)
+  }
+
   const handleClose = () => {
     setCopied(false)
     onClose()
   }
 
+  const isModified = editedContent !== content
+
   return (
     <Modal isOpen={isOpen} onClose={handleClose} title="Export Preview" size="xl">
-      {/* Filename and format info */}
-      <p className="mb-3 text-sm text-white/70">
-        Filename: <span className="font-mono text-white">{filename}</span>
-        <span className="ml-3 rounded bg-white/10 px-2 py-0.5 text-xs text-white/70">
-          {format === 'markdown' ? 'Markdown' : format === 'html' ? 'HTML' : 'Plain Text'}
-        </span>
-      </p>
-
-      {/* Content Preview */}
-      <div
-        className={cn(
-          'max-h-96 overflow-auto rounded-md border border-white/10 bg-black/50 p-4',
-          'font-mono text-sm text-white'
-        )}
-      >
-        <pre className="whitespace-pre-wrap">{content}</pre>
+      {/* Filename, format info, and controls */}
+      <div className="mb-3 flex flex-wrap items-center justify-between gap-2">
+        <p className="text-sm text-white/70">
+          Filename: <span className="font-mono text-white">{filename}</span>
+          <span className="ml-3 rounded bg-white/10 px-2 py-0.5 text-xs text-white/70">
+            {format === 'markdown' ? 'Markdown' : format === 'html' ? 'HTML' : format === 'psa' ? 'PSA' : 'Plain Text'}
+          </span>
+          {isModified && (
+            <span className="ml-2 text-xs text-yellow-400">(edited)</span>
+          )}
+        </p>
+        <div className="flex items-center gap-3">
+          {onToggleSummary && (
+            <label className="flex items-center gap-2 text-sm text-white/60 cursor-pointer">
+              <input
+                type="checkbox"
+                checked={includeSummary}
+                onChange={(e) => onToggleSummary(e.target.checked)}
+                className="h-4 w-4 rounded border-white/20 bg-black/50"
+              />
+              Include Summary
+            </label>
+          )}
+          {isModified && (
+            <button
+              type="button"
+              onClick={handleReset}
+              className="flex items-center gap-1 text-xs text-white/40 hover:text-white"
+              title="Reset to original"
+            >
+              <RotateCcw className="h-3 w-3" />
+              Reset
+            </button>
+          )}
+        </div>
       </div>
 
+      {/* Editable Content */}
+      <label htmlFor="export-content" className="sr-only">
+        Export content
+      </label>
+      <textarea
+        id="export-content"
+        value={editedContent}
+        onChange={(e) => setEditedContent(e.target.value)}
+        className={cn(
+          'h-96 w-full resize-y rounded-md border border-white/10 bg-black/50 p-4',
+          'font-mono text-sm text-white',
+          'focus:border-white/30 focus:outline-none focus:ring-1 focus:ring-white/20'
+        )}
+      />
+
       {/* Actions */}
       <div className="mt-4 flex items-center justify-end gap-2">
         <button
+          type="button"
           onClick={handleCopy}
           className={cn(
             'flex items-center gap-2 rounded-md border border-white/10 px-3 py-2 text-sm font-medium',
@@ -86,6 +136,7 @@ export function ExportPreviewModal({
           )}
         </button>
         <button
+          type="button"
           onClick={handleDownload}
           className={cn(
             'flex items-center gap-2 rounded-md bg-white px-3 py-2 text-sm font-medium text-black',