fix(desktop): image rendering for Windows paths and MEDIA: prefix

- toFileUrl: normalize backslashes, detect Windows drive-letter paths
- resolveFileUrl: strip MEDIA: prefix from tool results, Windows path support
- handleServe: skip prepending "/" for Windows drive-letter URL paths

internal/http/files.go

@@ -107,7 +107,13 @@ func (h *FilesHandler) handleServe(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// URL path is the absolute path with leading "/" stripped (e.g. "app/.goclaw/workspace/file.png")
-	absPath := filepath.Clean("/" + urlPath)
+	// Windows drive letter: "C:/Users/..." → use directly without prepending "/"
+	var absPath string
+	if len(urlPath) >= 2 && urlPath[1] == ':' {
+		absPath = filepath.Clean(urlPath)
+	} else {
+		absPath = filepath.Clean("/" + urlPath)
+	}
 
 	// Block access to sensitive system directories
 	for _, prefix := range deniedFilePrefixes {

ui/desktop/frontend/src/components/chat/MarkdownRenderer.tsx

@@ -28,13 +28,21 @@ function resolveFileUrl(path: string, baseUrl?: string): string {
     if (isApiClientReady()) return getApiClient().getBaseUrl() + path
     return path
   }
+  // Strip MEDIA: prefix (tool results embed paths as MEDIA:/path/to/file.png)
+  const clean = path.replace(/^MEDIA:/, '')
+  // Normalize backslashes (Windows paths: C:\Users\... → C:/Users/...)
+  const normalized = clean.replace(/\\/g, '/')
   // Relative path with baseUrl — resolve against the base directory
-  if (baseUrl && !path.startsWith('/')) {
+  if (baseUrl && !normalized.startsWith('/') && !/^[a-zA-Z]:\//.test(normalized)) {
     const baseDir = baseUrl.substring(0, baseUrl.lastIndexOf('/') + 1)
-    return baseDir + path
+    return baseDir + normalized
   }
-  // Absolute path — preserve full path for direct file serving
-  const filePath = path.startsWith('/') ? `/v1/files${path}` : `/v1/files/${path.split('/').pop() ?? path}`
+  // Absolute path: Unix /... or Windows C:/...
+  const filePath = normalized.startsWith('/')
+    ? `/v1/files${normalized}`
+    : /^[a-zA-Z]:\//.test(normalized)
+      ? `/v1/files/${normalized}`
+      : `/v1/files/${normalized.split('/').pop() ?? normalized}`
   if (isApiClientReady()) return getApiClient().getBaseUrl() + filePath
   return filePath
 }

ui/desktop/frontend/src/hooks/use-chat.ts

@@ -10,11 +10,13 @@ import type { AttachedFile } from '../components/chat/InputBar'
 // can resolve the file directly without findInWorkspace fallback.
 function toFileUrl(path: string): string {
   if (!path) return ''
-  if (path.startsWith('/v1/files/') || path.includes('/v1/files/')) return resolveBase(path)
-  // Absolute path — preserve full path for direct file serving
-  if (path.startsWith('/')) return resolveBase(`/v1/files${path}`)
-  const basename = path.split('/').pop() ?? path
-  return resolveBase(`/v1/files/${basename}`)
+  if (path.includes('/v1/files/')) return resolveBase(path)
+  // Normalize backslashes (Windows paths: C:\Users\... → C:/Users/...)
+  const normalized = path.replace(/\\/g, '/')
+  // Absolute: Unix /... or Windows C:/...
+  if (normalized.startsWith('/')) return resolveBase(`/v1/files${normalized}`)
+  if (/^[a-zA-Z]:\//.test(normalized)) return resolveBase(`/v1/files/${normalized}`)
+  return resolveBase(`/v1/files/${normalized.split('/').pop() ?? normalized}`)
 }
 
 function resolveBase(path: string): string {