Hopefully final fix to infinite loop bug

[vcarl]

This should fix the issue we've been seeing with crashes on invalid messages. Specifically the issue was because the array that was being shifted was not the same one being iterated on, thus the infinite loop.

Now the shift is a) done on the correct array, b) performed immediately after getting a reference to the underlying message, which should resolve the infinite loops we've been experiencing

We'll see if this also fixes the incorrect behavior I've seen where old forhire posts aren't reliably cleared out.

[ghost]

👇 Click on the image for a new way to code review

Legend

[what-the-diff]

PR Summary

• Introduced a helper function
  The partition function from another helper file has been brought into job-mod-helpers.ts. This may help with array handling in this file.

• Created a new variable for job messages
  A new object named jobBoardMessageCache has been introduced, which is used for storing job related messages. It contains two properties, namely forHire and hiring which are initialized as empty arrays.

• Improved message handling in loadJobs function
  The logic for filtering and adding new messages to jobBoardMessageCache was remodeled, which will likely improve how job messages are managed.

• Removed unnecessary logging
  The logger import was cut off from the top in job-mod-helpers.ts. This simplifies the code and reduces unnecessary dependencies.

• Revamped the deleteAgedPosts function
  The logic for creating forHirePosts and shifting methods for jobBoardMessageCache were restructured. Also, an unnecessary break statement after logging was removed, enhancing efficiency and readability for managing aged job posts.

• Transformed the updateJobs function
  Changes were made in how the type is used and where messages are added in jobBoardMessageCache, enhancing ease and accuracy of tracking job updates.

• Added a new function and updated an import in validate.ts
  A getLastPostAge function, which could be used to determine the age of the latest post, was introduced. A corresponding import was updated in this file.

• Modified age tracking in participation function
  The way lastSent data is determined was changed, potentially improving how we track post participation over time.