Add automatic JWT token refresh capability for long running jobs

[maclarel]

JWTs granted through GitHub App usage have a ~1 hour lifespan, and this can be hit if rate limits are encountered or if data extraction simply takes longer than that (e.g. large org, significant numbers of workflows, etc...).

This PR introduces logic that will attempt to refresh an existing session in the event that 401 errors are encountered during extraction (indicating the token has expired), or if the token is > 50 minutes old, hard-failing after a handful of attempts to do so.

This PR was heavily AI-assisted so review from someone with better knowledge of GitHound's auth flow than me should certainly give it a review. It should be fully backwards compatible, does not appear to introduce any breaking changes, and is (so far) working as expected in my own testing.

Example:

...
WARNING: Rate limit hit when doing Github RestAPI call. Retry 1/3
Reached rate limit. Sleeping for 2394 seconds. Tokens reset at unix time 1776796891
WARNING: Received 401 Unauthorized. Attempting token refresh...
Refreshing GitHub App installation token...
GitHub App installation token refreshed. New expiry: 04/21/2026 19:41:32 +00:00
...