fix(msteams): detect windows local paths for uploads

extensions/msteams/src/media-helpers.test.ts

@@ -145,6 +145,15 @@ describe("msteams media-helpers", () => {
       expect(isLocalPath("~/Downloads/image.png")).toBe(true);
     });
 
+    it("returns true for Windows absolute drive paths", () => {
+      expect(isLocalPath("C:\\Users\\test\\image.png")).toBe(true);
+      expect(isLocalPath("D:/data/photo.jpg")).toBe(true);
+    });
+
+    it("returns true for Windows UNC paths", () => {
+      expect(isLocalPath("\\\\server\\share\\image.png")).toBe(true);
+    });
+
     it("returns false for http URLs", () => {
       expect(isLocalPath("http://example.com/image.png")).toBe(false);
       expect(isLocalPath("https://example.com/image.png")).toBe(false);

extensions/msteams/src/media-helpers.ts

@@ -65,7 +65,21 @@ export async function extractFilename(url: string): Promise<string> {
  * Check if a URL refers to a local file path.
  */
 export function isLocalPath(url: string): boolean {
-  return url.startsWith("file://") || url.startsWith("/") || url.startsWith("~");
+  if (url.startsWith("file://") || url.startsWith("/") || url.startsWith("~")) {
+    return true;
+  }
+
+  // Windows drive-letter absolute path (e.g. C:\foo\bar.txt or C:/foo/bar.txt)
+  if (/^[a-zA-Z]:[\\/]/.test(url)) {
+    return true;
+  }
+
+  // Windows UNC path (e.g. \\server\share\file.txt)
+  if (url.startsWith("\\\\")) {
+    return true;
+  }
+
+  return false;
 }
 
 /**