Add Tool Filtering to Agent Config

[WillFleming]

This PR adds support for filtering tools available to an agent via include_tools and exclude_tools parameters.

Summary

• New AgentConfig fields: include_tools and exclude_tools (lists of {server}-{tool} strings)
• Tools are filtered at initialization; exclusion takes precedence over inclusion
• Makes it easy to restrict or customize tool access per agent

Examples

@agent(
    name="search_agent",
    servers=["search-api"],
    include_tools=["search-api-web_search"]
)

@agent(
    name="safe_file_agent",
    servers=["file-system"],
    exclude_tools=["file-system-delete_file"]
)

Useful for limiting tool access in multi-agent setups or when integrating with third-party tool servers.

[evalstate]

Thanks @WillFleming -- this is a great feature.

Couple of questions/information if you're open to collaborate further on this:

1. We've begun using AgentCard and AgentSkill types from the A2A Protocol internally to describe Agents and their Types. It's early days, but you can see in router_agent.py and

   fast-agent/src/mcp_agent/agents/base_agent.py

   Lines 662 to 679 in 7cb3760

   	async def convert(self, tool: Tool) -> AgentSkill:
   	"""
   	Convert a Tool to an AgentSkill.
   	"""
   	_, tool_without_namespace = await self._parse_resource_name(tool.name, "tool")
   	return AgentSkill(
   	id=tool.name,
   	name=tool_without_namespace,
   	description=tool.description,
   	tags=["tool"],
   	examples=None,
   	inputModes=None, # ["text/plain"],
   	# cover TextContent | ImageContent ->
   	# https://github.com/modelcontextprotocol/modelcontextprotocol/pull/223
   	# https://github.com/modelcontextprotocol/modelcontextprotocol/pull/93
   	outputModes=None, # ,["text/plain", "image/*"],
   	)

   the beginnings of mapping Tools to Skills. It feels like this might be a good way to go (but it's early days).

2. The consideration of whether this should be a runtime or configuration time decision (or controllable both ways).

I'd be interested in your thoughts on the above and thank you for the PR so far :)