Fix Windows path handling in VSCode extension context menu (issue #1504) (#1903)

* Initial plan

* Fix Windows path handling in VSCode extension context menu

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

* Add tests for Windows path handling fix

Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pelikhan <4175913+pelikhan@users.noreply.github.com>
Co-authored-by: Peli de Halleux <pelikhan@users.noreply.github.com>

Author: Copilot

packages/core/test/resources.test.ts

@@ -100,4 +100,31 @@ describe("resources", async () => {
     assert(result.files[0].filename.includes("readme.md"));
   });
   */
+  
+  await test("should reject Windows-style paths that look like URIs (issue #1504)", async () => {
+    // This tests the issue fixed in VSCode extension
+    // Windows paths like "c:\Users\..." should not be treated as valid resources
+    const windowsPath = "c:\\Users\\test\\file.txt";
+    
+    const result = await tryResolveResource(windowsPath);
+    
+    // This should return undefined because it's not a valid resource
+    // The fix in VSCode extension ensures we pass file:// URIs instead
+    assert.equal(result, undefined);
+  });
+
+  await test("should handle proper file URIs correctly (issue #1504 fix)", async () => {
+    // This tests what the VSCode extension fix ensures is sent
+    const testFilePath = join(tempDir, "test-file.txt");
+    writeFileSync(testFilePath, "test content");
+    
+    // Convert to proper file URI (what VSCode should send after our fix)
+    const fileUri = pathToFileURL(testFilePath).href;
+    
+    const result = await tryResolveResource(fileUri);
+    
+    assert(result);
+    assert.equal(result.files.length, 1);
+    assert.equal(result.files[0].filename, testFilePath);
+  });
 });

packages/vscode/src/fragmentcommands.ts

@@ -82,7 +82,7 @@ export function activateFragmentCommands(state: ExtensionState): void {
       parameters = await showPromptParametersQuickPicks(script, defaultValues);
       if (parameters === undefined) return;
       scriptId = script.id;
-      files = fileOrFolders?.map((f) => f.fsPath) || [fileOrFolder?.fsPath];
+      files = fileOrFolders?.map((f) => f.toString()) || [fileOrFolder?.toString()];
     }
     await state.requestAI({
       fragment: { files: files.filter((f) => !!f) },