v1.7.5

release: v1.7.5

Internal refactor and one bug fix; no user-facing behaviour change.

- fix(schedule): truncate previews on char boundaries (no more panic on
  multi-byte/emoji content in schedule list/add/fire)
- refactor: remove dead timing-analytics methods and an unused wrapper
- refactor(xapi): fold engagement verbs, share the pagination loop and
  tweet-listing tail, drop a throwaway clone in get_tweet
- refactor(errors): convert rusqlite errors via From in the tracker
- style: clear the items-after-test-module clippy warning

Claude-Session: https://claude.ai/code/session_01TXjeyZcV3Qr6CozGBmCi7s