docs: document the 'Use *.dev.localhost URLs?' interactive prompt for aspire new

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Co-authored-by: IEvangelist <7679720+IEvangelist@users.noreply.github.com>

Author: Copilot

src/frontend/src/content/docs/reference/cli/commands/aspire-new.mdx

@@ -33,6 +33,45 @@ This command defaults to **interactive** mode. When executed without any options
   with Aspire templates as an alternative for project creation.
 </Aside>
 
+## Interactive prompts
+
+When running `aspire new` in interactive mode, the command asks one or more questions before generating the project. The available prompts depend on the template and options you provide.
+
+### Use \*.dev.localhost URLs?
+
+During project creation, you may be prompted:
+
+> **Use \*.dev.localhost URLs?**
+
+This prompt determines whether the generated launch profile configures your Aspire services to be accessible via `*.dev.localhost` wildcard subdomain URLs (for example, `https://myservice.dev.localhost`) instead of standard `http://localhost` with port numbers.
+
+#### What are \*.dev.localhost URLs?
+
+`*.dev.localhost` is a wildcard subdomain pattern that resolves to your local machine (`127.0.0.1` or `::1`) in all modern browsers—no DNS or hosts-file configuration is required. The ASP.NET Core HTTPS development certificate includes `*.dev.localhost` as a Subject Alternative Name (SAN), so browsers trust connections to any subdomain under `*.dev.localhost` when the certificate is installed and trusted.
+
+#### Yes — use \*.dev.localhost URLs
+
+Choosing **Yes** configures the generated project so that each service gets a unique subdomain URL such as `https://myservice.dev.localhost`. This option:
+
+- Enables HTTPS for all services from the start, leveraging the wildcard development certificate.
+- Gives each service its own origin, which prevents cookie and authentication token collisions between services running on the same machine.
+- More closely mirrors a production setup where services are hosted on separate (sub)domains.
+
+**Prerequisite:** The ASP.NET Core HTTPS development certificate must be installed and trusted on your machine. Run the following command if you haven't done so already:
+
+```bash
+dotnet dev-certs https --trust
+```
+
+<Aside type="note">
+  Safari on macOS does not resolve `*.localhost` subdomains to `127.0.0.1` by
+  default. If you use Safari, choose **No** or add an entry to your hosts file.
+</Aside>
+
+#### No — use standard localhost URLs (default)
+
+Choosing **No** (the default) configures services with standard `http://localhost:<port>` addresses. This option requires no certificate setup and works in all browsers and tools without additional configuration.
+
 ## Options
 
 The following options are available: