docs(spikes): Deno 2.9.7 + TS 7 compatibility spike and ADR-004

Co-Authored-By: Claude Fable 5.1 <[email protected]>

spikes/deno/apps/server/vitest.config.ts

@@ -0,0 +1,6 @@
+import { defineConfig } from "vitest/config";
+// Vite's resolver does not read deno.json workspace/imports: map workspace members manually.
+export default defineConfig({
+  resolve: { alias: { "@spike/x": new URL("../../packages/x/src/mod.ts", import.meta.url).pathname } },
+  test: { include: ["test/**/*.test.ts"] },
+});