Enhance documentation for folder management and nested folder support…

[Adityav369]

… across SDK methods. Update parameters to include folder_name and folder_depth for scoping in various document and graph operations.

[jazzberry-ai]

Bug Report

Name	Severity	Example test case	Description
Folder Depth Bypass	High	Call retrieve_chunks with folder_name="/" and folder_depth=-1	If the server-side code does not properly validate the folder_depth parameter, a malicious user could potentially bypass folder scoping and access documents in folders they are not authorized to access.

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