fix: pass baseDir to file preview API to fix Windows cross-drive 403

FilePreview and DocPreview components were not passing baseDir to
the preview API, causing 403 "File is outside the allowed scope"
on Windows when the project is on a different drive than home.

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

Author: 7418

src/components/layout/DocPreview.tsx

@@ -13,6 +13,7 @@ import { cjk } from "@streamdown/cjk";
 import { code } from "@streamdown/code";
 import { math } from "@streamdown/math";
 import { mermaid } from "@streamdown/mermaid";
+import { usePanel } from "@/hooks/usePanel";
 import type { FilePreview as FilePreviewType } from "@/types";
 
 const streamdownPlugins = { cjk, code, math, mermaid };
@@ -52,6 +53,7 @@ export function DocPreview({
   width,
 }: DocPreviewProps) {
   const { resolvedTheme } = useTheme();
+  const { workingDirectory } = usePanel();
   const isDark = resolvedTheme === "dark";
   const [preview, setPreview] = useState<FilePreviewType | null>(null);
   const [loading, setLoading] = useState(true);
@@ -66,7 +68,7 @@ export function DocPreview({
       setError(null);
       try {
         const res = await fetch(
-          `/api/files/preview?path=${encodeURIComponent(filePath)}&maxLines=500`
+          `/api/files/preview?path=${encodeURIComponent(filePath)}&maxLines=500${workingDirectory ? `&baseDir=${encodeURIComponent(workingDirectory)}` : ''}`
         );
         if (!res.ok) {
           const data = await res.json();

src/components/project/FilePreview.tsx

@@ -8,6 +8,7 @@ import { Badge } from "@/components/ui/badge";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { Light as SyntaxHighlighter } from "react-syntax-highlighter";
 import { atomOneDark } from "react-syntax-highlighter/dist/esm/styles/hljs";
+import { usePanel } from "@/hooks/usePanel";
 import type { FilePreview as FilePreviewType } from "@/types";
 
 interface FilePreviewProps {
@@ -16,6 +17,7 @@ interface FilePreviewProps {
 }
 
 export function FilePreview({ filePath, onBack }: FilePreviewProps) {
+  const { workingDirectory } = usePanel();
   const [preview, setPreview] = useState<FilePreviewType | null>(null);
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
@@ -27,7 +29,7 @@ export function FilePreview({ filePath, onBack }: FilePreviewProps) {
       setError(null);
       try {
         const res = await fetch(
-          `/api/files/preview?path=${encodeURIComponent(filePath)}`
+          `/api/files/preview?path=${encodeURIComponent(filePath)}${workingDirectory ? `&baseDir=${encodeURIComponent(workingDirectory)}` : ''}`
         );
         if (!res.ok) {
           const data = await res.json();