feat(generators): ui byte-identical snapshot + dispatch entry + e2e test

- Adds ui.snapshot.json (28 entries) computed from packages/core-ui
- Wires CORE_PACKAGE_GENERATORS["ui"]: guard + emitTemplateTree +
  addToTranspilePackages + printUiNextSteps (web-tanstack/storybook
  wiring is printed, not generated — resists templating)
- Adds "ui" to the core-package generator choices list
- Adds core-package-ui.e2e.test.ts (byte-identical reconstruction)
  — passes in 14.6 s

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

turbo/generators/config.ts

@@ -654,6 +654,18 @@ import noRealtimeHandlerReexport from "./rules/no-realtime-handler-reexport.js";
         },
         printTrpcNextSteps,
       ],
+      ui: () => [
+        () => {
+          assertOptionalPackageNotPresent("core-ui");
+          return "Guard passed — packages/core-ui does not exist yet.";
+        },
+        ...emitTemplateTree("core-package/ui", "packages/core-ui"),
+        () => {
+          addToTranspilePackages("apps/web-next/next.config.mjs", "@repo/core-ui");
+          return "Added @repo/core-ui to transpilePackages.";
+        },
+        printUiNextSteps,
+      ],
     };
 
   plop.setGenerator("core-package", {
@@ -663,7 +675,7 @@ import noRealtimeHandlerReexport from "./rules/no-realtime-handler-reexport.js";
         type: "list",
         name: "name",
         message: "Which optional core package?",
-        choices: ["realtime", "events", "trpc"],
+        choices: ["realtime", "events", "trpc", "ui"],
       },
     ],
     actions: (answers) => {
@@ -1187,6 +1199,37 @@ function printTrpcNextSteps(): string {
   ].join("\n");
 }
 
+function printUiNextSteps(): string {
+  return [
+    "─────────────────────────────────────────────────────────────",
+    "@repo/core-ui scaffolded.",
+    "",
+    "Next steps (manual wiring — not generated):",
+    "",
+    "  1. pnpm install   # link the new workspace package",
+    "",
+    "  2. apps/web-next/package.json:",
+    '     - add "@repo/core-ui": "workspace:*" to dependencies',
+    "",
+    "  3. apps/storybook/.storybook/main.ts:",
+    '     - add "../../../packages/core-ui/src/**/*.stories.@(ts|tsx)" to the stories array',
+    "",
+    "  4. apps/storybook/.storybook/preview.ts:",
+    '     - add: import "@repo/core-ui/styles/globals.css";',
+    "",
+    "  5. apps/storybook/package.json:",
+    '     - add "@repo/core-ui": "workspace:*" to dependencies',
+    "",
+    "  6. apps/web-tanstack/package.json:",
+    '     - add "@repo/core-ui": "workspace:*" to dependencies',
+    "     - when TanStack Start gains a real vite.config.ts, add @repo/core-ui",
+    "       to optimizeDeps.include",
+    "",
+    "  7. pnpm typecheck && pnpm lint && pnpm test",
+    "─────────────────────────────────────────────────────────────",
+  ].join("\n");
+}
+
 function printEventsNextSteps(): string {
   return [
     "─────────────────────────────────────────────────────────────",