Add tools property to ContainerAgent.yaml

[therealjohn]

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.