docs/types: clarify abort flow, zod schema limits, file batch args, and files.content response type

[however-yir]

Summary

• clarify the Abort on a function call helper example and document expected behavior after intentional aborts
• fix polling helper examples with extra parentheses typos
• clarify vectorStores.fileBatches.uploadAndPoll usage with { files: ... }
• add explicit files.content() usage docs in README showing Response.text() / Response.arrayBuffer()
• align FileContent type alias with runtime behavior (Response)

Issues addressed

• Fixes Abort on a function call example is confusing #996
• Fixes Assistants File Search Documentation Incorrect - Yields #1337
• Fixes clarify which zod features are supported #1017
• Fixes openai.files.content returns raw Response object #958

Testing

• docs/type-only changes
• repo lint not run locally because dependencies are not installed in this environment

[however-yir]

Hi maintainers, friendly ping for review when convenient.

This PR addresses #996, #1337, #1017, and #958 by:

• clarifying the abort example behavior in helpers.md
• fixing polling helper snippet typos
• clarifying fileBatches.uploadAndPoll argument shape
• documenting files.content() as returning a Response
• aligning the FileContent type alias accordingly

Scope is docs/types only (no API behavior changes). I couldn’t run repo lint locally in this environment because dependencies were not installed. Happy to revise quickly if you prefer a different wording or scope.