Add layered error boundaries to compliance portal

Introduce global, page, and section-level error handling for the
compliance portal so a failure is contained at the smallest possible
scope instead of blanking the whole page.

Add a portal-local Relay fetch that throws only request-level errors
(and always redirects on UNAUTHENTICATED) while leaving field-level
errors in the response, so Relay surfaces them at the reading component
through @throwOnFieldError and the nearest boundary. Add a NotFoundError
for node __typename mismatches mapped to a not-found page.

Ship reusable v2 kit primitives (ErrorBoundary, ErrorState, InlineError)
matching the Figma global/local/inline designs, wire the bootstrap and
route boundaries, and demonstrate section and row boundaries on the home
page. Update the error-handling and relay guides accordingly.

Signed-off-by: Émile Ré <emile@probo.com>

apps/compliance-portal/src/App.tsx

@@ -18,15 +18,19 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+import { ErrorBoundary } from "@probo/ui/src/v2/ErrorBoundary/ErrorBoundary";
 import { RouterProvider } from "react-router";
 
+import { BootstrapError } from "#/components/errors/BootstrapError";
 import { RelayProvider } from "#/lib/relay/RelayProvider";
 import { router } from "#/routes";
 
 export function App() {
   return (
-    <RelayProvider>
-      <RouterProvider router={router} />
-    </RelayProvider>
+    <ErrorBoundary fallback={<BootstrapError />}>
+      <RelayProvider>
+        <RouterProvider router={router} />
+      </RelayProvider>
+    </ErrorBoundary>
   );
 }