.NET: document Azure Functions trigger discovery

[he-yufeng]

Summary

• add a small local orchestration trigger to the 06_host_your_agent Azure Functions sample so the isolated worker indexes Durable Functions
• document why hosting-only apps may need one local [OrchestrationTrigger] for discovery
• add a troubleshooting note for missing hosted agent routes in the Azure Functions samples README

Refs #5927.

To verify

• dotnet build dotnet\samples\01-get-started\06_host_your_agent\06_host_your_agent.csproj --tl:off
• dotnet format dotnet\samples\01-get-started\06_host_your_agent\06_host_your_agent.csproj --include dotnet\samples\01-get-started\06_host_your_agent\DurableTriggerDiscovery.cs --verify-no-changes --no-restore --verbosity minimal
• git diff --check

[Copilot]

Pull request overview

Documents and mitigates an Azure Functions (.NET isolated) Durable Functions trigger discovery limitation that can prevent hosted agent HTTP routes from being indexed unless at least one durable trigger exists in the app assembly.

Changes:

• Added a note to the AzureFunctions hosting package README explaining the need for a local [OrchestrationTrigger] for trigger discovery in hosting-only apps.
• Added a minimal no-op orchestrator (DurableTriggerDiscovery) to the 06_host_your_agent Azure Functions sample to ensure Durable Functions indexing occurs.
• Added troubleshooting guidance to the Durable Agents Azure Functions samples README for missing hosted agent routes.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
dotnet/src/Microsoft.Agents.AI.Hosting.AzureFunctions/README.md	Documents the trigger discovery requirement and provides a minimal orchestrator example.
dotnet/samples/04-hosting/DurableAgents/AzureFunctions/README.md	Adds a troubleshooting note for when hosted agent routes don’t appear.
dotnet/samples/01-get-started/06_host_your_agent/DurableTriggerDiscovery.cs	Introduces a local no-op orchestrator to force Durable trigger discovery/indexing.

[he-yufeng]

Refreshed on current main. Local validation passed: dotnet build dotnet\samples\01-get-started\06_host_your_agent\06_host_your_agent.csproj --tl:off, dotnet format ... --verify-no-changes, and git diff --check.

[he-yufeng]

Rebased this branch onto current main and pushed the updated head bb219ae8.

Validation run locally from dotnet/:

• dotnet build .\samples\01-get-started\06_host_your_agent\06_host_your_agent.csproj -f net10.0 --tl:off -> passed, 0 warnings/errors
• git diff --check upstream/main..HEAD -> passed

The build log had transient NuGet EOF download messages, but restore retried/resolved and the project built successfully.

[he-yufeng]

Rebased this branch onto the latest upstream/main.

Validation from dotnet/:

• dotnet build .\samples\01-get-started\06_host_your_agent\06_host_your_agent.csproj -f net10.0 --tl:off
• git diff --check upstream/main..HEAD

The sample build completes with 0 warnings / 0 errors on the rebased head (6623a534).