Add Azure resource type samples

[willdavsmith]

Description

Adds 10 self-contained samples under samples/<app>/, each demonstrating a Radius resource type backed by an Azure recipe. Every sample includes a developer-facing app.bicep, a platform-facing env-azure.bicep, bicepconfig.json, and focused usage documentation.

Samples

Sample	Resource type	Application
kafka-ui	Radius.Messaging/kafka	Kafbat Kafka UI
berriai-litellm	Radius.AI/models	LiteLLM proxy
mongo-express-mongo-express	Radius.Data/mongoDatabases	mongo-express
dockersamples-todo-list-app	Radius.Data/mySqlDatabases	Docker todo-list app
sosedoff-pgweb	Radius.Data/postgreSqlDatabases	pgweb
warpstreamlabs-bento	Radius.Messaging/rabbitMQ	Bento streaming pipeline
radius-project-samples-demo	Radius.Data/redisCaches	Radius demo app
sqlpad-sqlpad	Radius.Data/sqlServerDatabases	SQLPad
azure-search-api	Radius.AI/search	Go Azure AI Search API
drakkan-sftpgo	Radius.Storage/objectStorage	SFTPGo

Highlights

• Nine samples build their workload from source through Radius.Compute/containerImages and run the resulting imageReference.
• kafka-ui uses the pinned official image because maintained Kafka UIs require a prebuilt JAR rather than offering a self-contained source-build Dockerfile.
• azure-search-api adds a standard-library Go service with health, indexing, and query endpoints plus unit tests.
• sqlpad-sqlpad replaces a one-shot migration probe with a long-running Azure SQL UI. SQLPad is pinned to v7.5.7; upstream archived the project in August 2025.
• Bento runs a continuous producer/consumer pipeline instead of a one-shot verification script.
• Sensitive recipe outputs retain the nested outputs.secrets { ... } contract and are consumed through properties.secrets plus secretKeyRef.
• BuildKit push credentials and Kubernetes image-pull credentials are documented separately. Users must provide a pushable registry and ensure built images are publicly readable or configure an image-pull secret.

Validation

• Azure Search API: go test ./..., go vet ./..., and formatting checks pass.
• SQLPad and other samples without recipe-produced secrets compile against the current published Radius extension.
• Samples using nested recipe secrets currently fail Bicep validation against br:biceptypes.azurecr.io/radius:latest because that artifact still exposes the older flat secret schema (BCP053/BCP036). The samples intentionally preserve the nested contract and require the published Radius extension to be regenerated with that schema.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[Reshrahim]

Thanks for adding them in! LGTM

Couple of things to do later

1. Merge all samples into one set with all the existing muti tier samples like eshop updated to use extensibility
2. bicepconfig.json seems same across the samples. I wonder if we need them
3. We should cross reference contrib repo for type definitions and other context