Add tools property to ContainerAgent.yaml

Add tools property to ContainerAgent.yaml, reusing the existing McpTool.yaml schema that PromptAgent already has.

To support the Toolbox feature in Foundry, hosted agents need tools defined that are in Foundry. Toolboxes are MCP endpoints, so we can reuse the MCPTool schema:

Example:

 name: echo-agent
 kind: hosted
 protocols:
   - protocol: responses
     version: v1
 tools:
   - kind: mcp                                                      # McpTool.yaml
     serverName: echo-github-toolbox               # toolbox name
     connection:                                                   # FoundryConnection.yaml
       kind: foundry
       endpoint: ${FOUNDRY_TOOLSET__ECHO_GITHUB_TOOLSET__ENDPOINT}   # azd, vsc replaces this value in deployment
       name: echo-github-toolbox
       connectionType: toolbox
     approvalMode: auto
     allowedTools:
       - search_docs
       - create_issue

Also noting connectionType: toolbox as a valid value for FoundryConnection.

The tooling can use this to make sure the toolbox is created/updated.

Start with ContainerAgent.yaml and compare its structure with the existing McpTool.yaml schema used by PromptAgent. Check FoundryConnection.yaml for the connectionType values, then update the schemas so ContainerAgent tools can use MCP tools and toolbox connections. Done means the example configuration validates with connectionType: toolbox and the existing schema relationships remain valid.