Add `_meta` for `tools/list` method in MCP Toolbox.
If there are authorized invocation, the following will be return in
`_meta`:
```
{
"name":"my-tool-name",
"description":"my tool description",
"inputSchema":{
"type":"object",
"properties":{
"user_id":{"type":"string","description":"user's name from google login"}
},
"required":["user_id"]
},
"_meta":{
"toolbox/authParam":{"user_id":["my_auth"]}
}
}
```
If there are authenticated parameter, the following will be return in
`_meta`:
```
{
"name":"my-tool-name",
"description":"my tool description",
"inputSchema":{
"type":"object",
"properties":{
"sql":{"type":"string","description":"The sql to execute."}
},
"required":["sql"]
},
"_meta":{
"toolbox/authInvoke":["my_auth"]
}
}
```
If there are no authorized invocation or authenticated prameter, the
`_meta` field will be omitted.
With this feature, the following were updated in the source code:
* In each `func(p CommonParameter) McpManifest()`, we will return a
`[]string` for the list of authenticated parameters. This is similar to
how Manifest() return the list of authNames in non-MCP Toolbox's
manifest.
* The `func(ps Parameters) McpManifest()` will return a
`map[string][]string` that with key as param's name, and value as the
param's auth.
* Added a new function `GetMcpManifest()` in `tools.go`. This function
will consctruct the McpManifest, and add the `Metadata` field.
* Associated tests were added or updated.
Update `tool.Invoke()` to return type `any` instead of `[]any`.
Toolbox return a map with the `results` key, and the SDK reads the
string from the key. So this won't break existing SDK implementation.
Fixes#870
