Slack API Refactor

[obelisk]

I revisited the Slack API because I wanted to add the ability to fetch user info (specifically timezone data) and I was unhappy with how I previously structured the code. There was no clear separation of responsibilities and it was hard to see how APIs were implemented and especially difficult to add new ones.

This changes all of that and couples the STL and the Plaid library together to throw compile time errors for inconsistencies rather than runtime ApiError::MissingParameter errors.

[Copilot]

Pull Request Overview

This PR refactors the Slack API integration to improve clarity and enforce compile‑time consistency for API calls by restructuring request builders and error handling.

• Introduces new helper functions in the Slack API module to build GET and POST requests and centralizes token management.
• Converts loosely structured parameter mappings into strongly typed JSON structures in the Plaid STL module.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
runtime/plaid/src/apis/slack/api.rs	Refactored API calls with dedicated builder functions and improved error handling.
runtime/plaid-stl/src/slack/mod.rs	Switched from generic HashMap to defined structs for message and view parameters.

Comments suppressed due to low confidence (1)

runtime/plaid/src/apis/slack/api.rs:45

• [nitpick] The current implementation of 'uri_params' requires callers to format the entire query string manually. Consider modifying this function to accept key-value pairs for query parameters to make it more robust and less error‑prone.

fn request_builder<T: AsRef<str>>(client: &Client, api: &Apis, token: String, uri_params: Option<T>) -> RequestBuilder {

[timweri]

Clean!