Adds the following tools for Postgres:
(1) list_table_stats: Lists table statistics in the database. .
<img width="3446" height="1304" alt="image"
src="https://github.com/user-attachments/assets/68951edc-8d99-460e-a1ac-2d3da9388baf"
/>
<img width="2870" height="1338" alt="image"
src="https://github.com/user-attachments/assets/100a3b7d-202d-4dfd-b046-5dab4390ba41"
/>
> Should include a concise description of the changes (bug or feature),
it's
> impact, along with a summary of the solution
## PR Checklist
> Thank you for opening a Pull Request! Before submitting your PR, there
are a
> few things you can do to make sure it goes smoothly:
- [x] Make sure you reviewed
[CONTRIBUTING.md](https://github.com/googleapis/genai-toolbox/blob/main/CONTRIBUTING.md)
- [x] Make sure to open an issue as a
[bug/issue](https://github.com/googleapis/genai-toolbox/issues/new/choose)
before writing your code! That way we can discuss the change, evaluate
designs, and agree on the general idea
- [x] Ensure the tests and linter pass
- [x] Code coverage does not decrease (if any source code was changed)
- [x] Appropriate docs were updated (if necessary)
- [x] Make sure to add `!` if this involve a breaking change
🛠️Fixes#1738
