test scss‑navigation : verify scheme‑prefixed @import paths remain absolute

Adds `schemeImportLinks.test.ts` with four mocha cases covering
`http://`, `https://`, `file://`, and `vscode-resource://` URLs

Author: IsaacTian05

src/test/scss/schemeImportLinks.test.ts

@@ -0,0 +1,46 @@
+import * as assert from 'assert';
+import { getSCSSLanguageService } from '../../scssLanguageService';
+import { TextDocument } from 'vscode-languageserver-textdocument';
+import { DocumentContext } from '../../cssLanguageTypes';
+
+function createDocument(contents: string, uri = 'file:///test.scss') {
+  return TextDocument.create(uri, 'scss', 0, contents);
+}
+
+const dummyContext: DocumentContext = {
+  resolveReference: (ref: string, _base: string) => ref
+};
+
+const ls = getSCSSLanguageService();
+
+async function getLinks(contents: string) {
+  const doc = createDocument(contents);
+  const stylesheet = ls.parseStylesheet(doc);
+  return ls.findDocumentLinks2(doc, stylesheet, dummyContext);
+}
+
+describe('SCSS Navigation – scheme URL imports', () => {
+  it('http scheme import is treated as absolute URL, not bare import', async () => {
+    const links = await getLinks(`@import "http://example.com/foo.css";`);
+    assert.strictEqual(links.length, 1);
+    assert.strictEqual(links[0].target, 'http://example.com/foo.css');
+  });
+
+  it('https scheme import is treated as absolute URL, not bare import', async () => {
+    const links = await getLinks(`@import "https://cdn.example.com/reset.css";`);
+    assert.strictEqual(links.length, 1);
+    assert.strictEqual(links[0].target, 'https://cdn.example.com/reset.css');
+  });
+
+  it('file scheme import is treated as absolute URL, not bare import', async () => {
+    const links = await getLinks(`@import "file:///Users/test/project/styles/base.scss";`);
+    assert.strictEqual(links.length, 1);
+    assert.strictEqual(links[0].target, 'file:///Users/test/project/styles/base.scss');
+  });
+
+  it('custom scheme import (vscode-resource) is treated as absolute URL, not bare import', async () => {
+    const links = await getLinks(`@import "vscode-resource://file/some.css";`);
+    assert.strictEqual(links.length, 1);
+    assert.strictEqual(links[0].target, 'vscode-resource://file/some.css');
+  });
+});