[Issue] azure.ai.agents suggests removed `azd ai agent project set` command

[huimiu]

• Make sure you've installed the latest version using instructions

Output from azd version

N/A — found by code inspection on main.

Describe the bug

When the azure.ai.agents extension can't resolve a Foundry project endpoint, it returns a missing_project_endpoint error whose suggestion tells the user to run:

azd ai agent project set <endpoint>

That command no longer exists. It was moved to the azure.ai.projects extension as azd ai project set. The agents extension's own code acknowledges the removal — internal/cmd/project_context_store.go:18-19 describes projectContextConfigPath as "the legacy UserConfig path used by the removed azd ai agent project set command" — but the user-facing suggestion string was never updated.

Source: cli/azd/extensions/azure.ai.agents/internal/cmd/project_endpoint.go:126-134

func noProjectEndpointError() error {
	return exterrors.Dependency(
		exterrors.CodeMissingProjectEndpoint,
		"no Foundry project endpoint resolved",
		"persist a workspace default with `azd ai agent project set <endpoint>`, "+
			"or set FOUNDRY_PROJECT_ENDPOINT in the active azd environment, "+
			"or export FOUNDRY_PROJECT_ENDPOINT in your shell",
	)
}

This looks like a missed spot when the command moved. Every other extension emitting the same suggestion already has the correct text:

File	Suggested command
azure.ai.projects/internal/cmd/project_endpoint.go:135	azd ai project set ✅
azure.ai.connections/internal/foundry/projectctx/validator.go:108	azd ai project set ✅
azure.ai.toolboxes/internal/foundry/projectctx/validator.go:108	azd ai project set ✅
azure.ai.skills/internal/cmd/endpoint.go:191	azd ai project set ✅
azure.ai.agents/internal/cmd/project_endpoint.go:130	azd ai agent project set ❌

To Reproduce

1. Install the azure.ai.agents extension.
2. Make sure no project endpoint can be resolved — no FOUNDRY_PROJECT_ENDPOINT in the active azd environment or shell, and no persisted workspace default.
3. Run an agents command that resolves the project endpoint (for example azd ai agent eval without --project-endpoint).
4. Read the suggestion in the error output and run the command it names.

Expected behavior

The suggestion names a command that exists, so copy-pasting it works:

persist a workspace default with `azd ai project set <endpoint>`, or set
FOUNDRY_PROJECT_ENDPOINT in the active azd environment, or export
FOUNDRY_PROJECT_ENDPOINT in your shell

Actual behavior

The suggestion names the removed azd ai agent project set. A user who follows it hits an unknown-command error and has no working path forward from that message.

Why this matters

missing_project_endpoint is part of the largest Invalid Input bucket on azd deploy for agent services ("required project or environment configuration is missing", ~1.4% of deploys). The suggestion string is the main recovery path we give users for that failure, so pointing it at a removed command turns a recoverable error into a dead end.

Environment

N/A — affects all platforms.

Additional context

Fix is a one-line change to the suggestion string in noProjectEndpointError(), matching the wording already used by the other four extensions. project_endpoint_test.go:99-108 covers the error code and category but not the suggestion text, so a short assertion on the suggestion would keep the five copies from drifting again.