Add a counter to Stress app

[adamint]

Description

While investigating #9251, I ntoiced we were missing a counter in the stress playground app.

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No
• Does the change require an update in our Aspire docs?
  • Yes
    • Link to aspire-docs issue (consider using one of the following templates):
      • New (or update) doc-idea template
      • New breaking-change template
      • New diagnostic template
  • No

[Copilot]

Pull Request Overview

This PR adds a counter feature to the Stress playground app by registering a new hosted service and corresponding metrics meter. Key changes include:

• Registering CounterMetrics as a hosted service and adding its corresponding meter in Program.cs.
• Introducing a new CounterMetrics class that creates and increments a counter metric in a background loop.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
playground/Stress/Stress.TelemetryService/Program.cs	Added registration for the CounterMetrics hosted service and meter.
playground/Stress/Stress.TelemetryService/CounterMetrics.cs	New service that implements a counter metric using a background task loop.

Comments suppressed due to low confidence (1)

playground/Stress/Stress.TelemetryService/CounterMetrics.cs:16

• [nitpick] The metric name 'run.done.new.count' could be made more descriptive. Consider renaming it to something like 'counter.completedRuns' to better convey its purpose.

name: "run.done.new.count",

[Copilot]

Extracting the delay duration (20 milliseconds) into a named constant could enhance readability and maintainability.

Suggested change

	await Task.Delay(20, cancellationToken);
	await Task.Delay(DelayDurationMilliseconds, cancellationToken);

[inlineHamed]

take a look at these screen shots:

in the first one it said there was 585 new posts at 8:00:14 and 697 new posts at 8:00:34
few seconds later in the second shot it removed the 8:00:14 one
few seconds later in the third shot it remove the previous item and show a new one

Sometimes it even changes a value from past as i said in #9251

[adamint]

take a look at these screen shots:

in the first one it said there was 585 new posts at 8:00:14 and 697 new posts at 8:00:34 few seconds later in the second shot it removed the 8:00:14 one few seconds later in the third shot it remove the previous item and show a new one

Sometimes it even changes a value from past as i said in #9251

@inlineHamed please show the graph view as well