fix(test-isolation): apply central vitest guard to roadmap-dashboard sub-project

The roadmap-dashboard Vitest sub-project overrode setupFiles with only
its jsdom helper. Vitest replaces (does not merge) setupFiles in child
projects, so the central isolation guard at
packages/core/src/__test-utils__/vitest-setup.ts was silently bypassed
for the 94 roadmap-dashboard tests, leaving them able to touch the real
project .fusion / $HOME / child processes without the leak-detection
and AI-CLI block.

Prepend the central guard so it loads before the dashboard jsdom setup.
All 94 roadmap-dashboard tests still pass.

plugins/fusion-plugin-roadmap/vitest.config.ts

@@ -24,7 +24,10 @@ export default defineConfig({
           name: "roadmap-dashboard",
           environment: "jsdom",
           include: ["src/dashboard/**/__tests__/**/*.test.{ts,tsx}", "src/dashboard/**/*.test.{ts,tsx}"],
-          setupFiles: [fileURLToPath(new URL("./src/dashboard/test-setup.ts", import.meta.url))],
+          setupFiles: [
+            fileURLToPath(new URL("../../packages/core/src/__test-utils__/vitest-setup.ts", import.meta.url)),
+            fileURLToPath(new URL("./src/dashboard/test-setup.ts", import.meta.url)),
+          ],
         },
       },
       {