Add meta parameter support to tools, resources, templates, and prompts decorators

[jlowin]

This PR adds meta parameter support to all FastMCP component types (tools, resources, templates, and prompts), allowing developers to attach custom metadata to their MCP components.

Changes

Before

# No component types supported meta parameter
@mcp.tool()
def my_tool(): pass

@mcp.resource("resource://data")
def get_data(): pass

@mcp.prompt()
def my_prompt(): pass

After

# All component types now support meta parameter
@mcp.tool(meta={"version": "1.0", "author": "test"})
def my_tool(): pass

@mcp.resource("resource://data", meta={"version": "2.0", "team": "data"})
def get_data(): pass

@mcp.resource("resource://{param}", meta={"version": "2.1", "template": "dynamic"}) 
def get_template(param: str): pass

@mcp.prompt(meta={"version": "1.5", "purpose": "analysis"})
def my_prompt(): pass

Implementation

• Added meta parameter to all server decorator methods (@mcp.tool, @mcp.resource, @mcp.prompt)
• Updated all base classes and factory methods to support the meta parameter
• Meta data is properly passed through to MCP clients and can be used for versioning, authorship, or other application-specific purposes
• Updated documentation with examples and parameter descriptions