improve the azd tools experience

The azd tool experience appears at unexpected times, and recommends tools in a way that is too general. We can improve this with a different experience that isn't focused on an all-in-one Azure install experience and instead focused on the scenario.

On first turn, azd shows this experience:

```
Let's get your development environment ready.

Discover and install Azure development tools such as Azure CLI, GitHub Copilot CLI, and Azure AI extensions.
To skip this check, set AZD_SKIP_FIRST_RUN=true or run azd config set tool.firstRunCompleted true.

? Would you like to check your Azure development tools?: [Y/n] Yes
```

Here are the tools it checks:

```
✓ Azure CLI (2.83.0)
✓ GitHub Copilot CLI (1.0.66)
✓ Azure Tools VS Code Extension (0.12.4)
✓ Bicep VS Code Extension (0.41.2)
○ GitHub Copilot Chat VS Code Extension — not installed
○ Azure MCP Server — not installed
✓ azd AI Agent Extensions (0.1.42-preview-foundrytest.1)

All recommended tools are installed. You're all set!
```

There are these problems:
When starting with AZD AI, devs use `azd ai agent init` which doesn't show this (only triggers on azd init). So it appears during the next `azd provision` or `deploy` which is a disruptive time to ask about this.
It's installing things that are not needed for Foundry development - Azure Tools, Bicep VSC, Azure MCP, etc.
GitHub Copilot Chat VS Code Extension is not an extension anymore, it's included in VSC now.