feat(shared,tests): add error boundaries, lib utils, i18n messages, and integration tests

shared:

- Add class-filter, error-state, route-error, section-error-boundary, widget-boundary components

- Add ui/alert component

- Add constants directory

- Add breached-password, export-utils, permission-bitmap, rate-limit, resolve-action-error, route-permissions, route-resolver, type-guards lib

- Add i18n messages (en, zh-CN) for invitation-codes, parent, questions, rbac

tests:

- Add integration tests for elective

- Add tests/setup/empty-stub

scripts:

- Add update-md.cjs, tmp_append_en.ps1, tmp_merge_en.ps1 utilities

src/shared/components/ui/alert.tsx

@@ -0,0 +1,42 @@
+import * as React from "react"
+
+import { cn } from "@/shared/lib/utils"
+
+function Alert({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      role="alert"
+      data-slot="alert"
+      className={cn(
+        "relative w-full rounded-lg border px-4 py-3 text-sm grid has-[>svg]:grid-cols-[calc(var(--spacing)*4)_1fr] grid-cols-[0_1fr] has-[>svg]:gap-x-3 gap-y-0.5 items-start [&>svg]:size-4 [&>svg]:translate-y-0.5 [&>svg]:text-current",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function AlertTitle({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="alert-title"
+      className={cn("col-start-2 line-clamp-1 min-h-4 font-medium tracking-tight", className)}
+      {...props}
+    />
+  )
+}
+
+function AlertDescription({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="alert-description"
+      className={cn(
+        "text-muted-foreground col-start-2 grid justify-items-start gap-1 text-sm [&_p]:leading-relaxed",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Alert, AlertTitle, AlertDescription }