Closes #28475

Updates `rename` and `code_action` `input_schema` methods to use
`json_schema_for<T>()` which transforms standard JSONSchema into the
subset required by Gemini.
Also makes `input_schema` implementations consistent.
Tested tools against Gemini 2.5 Pro Preview, Zed Claude 3.7 Sonnet
Thinking, o3-mini

Release Notes:

- Agent Beta: Fixed error 400 `INVALID_ARGUMENT` when using Gemini with
`code_actions` or `rename` tools enabled.