fix(tanstackstart-react): Add workerd and worker export conditions

Add `workerd` and `worker` export conditions to the `.` entry in
package.json, pointing to `index.server.js`. This prevents the
Cloudflare Vite plugin's resolve conditions (`workerd`, `worker`,
`module`, `browser`) from falling through to the `browser` condition,
which would resolve to `index.client.js` and trigger TanStack Start's
import-protection plugin rejecting `*.client.*` files in the server
environment.

Users deploying to Cloudflare Workers will need `nodejs_compat` enabled
in their wrangler configuration.

A dedicated Cloudflare entrypoint (without `@sentry/node` dependency)
will be addressed in a follow-up PR.

Author: smorimoto

packages/tanstackstart-react/package.json

@@ -19,6 +19,14 @@
     "./package.json": "./package.json",
     ".": {
       "types": "./build/types/index.types.d.ts",
+      "workerd": {
+        "import": "./build/esm/index.server.js",
+        "require": "./build/cjs/index.server.js"
+      },
+      "worker": {
+        "import": "./build/esm/index.server.js",
+        "require": "./build/cjs/index.server.js"
+      },
       "browser": {
         "import": "./build/esm/index.client.js",
         "require": "./build/cjs/index.client.js"