refactor: consolidate e2e tests into src/e2e/

Move sprint and multi-session vscode tests from src/test/suite/ to src/e2e/.
All e2e tests now live in one directory. Create index.ts in src/e2e/ to load
all .vscode.test.js files. Update runTest.ts to point to new location.

Fixes architectural drift: e2e and vscode tests scattered across two dirs.

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

Author: mickeyperlstein

src/test/suite/index.ts src/e2e/index.tssrc/test/suite/index.ts renamed to src/e2e/index.ts

@@ -46,7 +46,7 @@ async function main() {
   delete process.env.ELECTRON_RUN_AS_NODE;
 
   const extensionDevelopmentPath = path.resolve(__dirname, '../../');
-  const extensionTestsPath       = path.resolve(__dirname, './suite/index');
+  const extensionTestsPath       = path.resolve(__dirname, '../e2e/index');
 
   // ── 1. Start standalone server ─────────────────────────────────────────────
   const serverProc = startServer();