Implement parameter descriptions in all relevant locations

This issue is a follow-up to PR #10440, which added support for parameter descriptions and custom input rendering. The next step is to implement parameter descriptions in various places throughout the codebase and UI.

**Tasks:**
- [ ] - In the app host, support parameter descriptions via the `PublishingPromptInput` type ([src/Aspire.Hosting/Backchannel/BackchannelDataTypes.cs](https://github.com/dotnet/aspire/blob/main/src/Aspire.Hosting/Backchannel/BackchannelDataTypes.cs)). Ensure this flows all the way to the CLI implementation.
- [ ] - For Bicep, update logic in `AsProvisioningParameter` ([src/Aspire.Hosting.Azure/AzureProvisioningResourceExtensions.cs](https://github.com/dotnet/aspire/blob/main/src/Aspire.Hosting.Azure/AzureProvisioningResourceExtensions.cs)) to set the description on parameters.
- [ ] - Update Docker Compose parameter translation ([src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs](https://github.com/dotnet/aspire/blob/main/src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs)) to support and understand parameter descriptions.

Reference: https://github.com/dotnet/aspire/pull/10440

Start by reviewing PR #10440, then trace parameter handling through PublishingPromptInput in src/Aspire.Hosting/Backchannel/BackchannelDataTypes.cs and the CLI flow. Inspect AsProvisioningParameter in src/Aspire.Hosting.Azure/AzureProvisioningResourceExtensions.cs and parameter translation in src/Aspire.Hosting.Docker/DockerComposeServiceExtensions.cs. Done means descriptions are preserved for the app host, Bicep, and Docker Compose outputs.

Written by the indexing model from the issue text.