refactor: replace zerolog with slog (#12)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

chore(lint): standardize max line length

fix(slack): consider user_not_found as non-retryable

fix(bitbucket): pagination

fix(bitbucket): 404 should be non-retryable in get source

refactor(bitbucket+jira): adjust activities to new timpani API

feat(bitbucket): diffstats

fix(bitbucket): lint warning

fix(bitbucket): support optional path in diff requests

fix(slack): honor requested delays in 429 responses