- on successful login, kick off scraping of logged-in user, their followees, and only-followed home timeline
- `--auto-open` flag now opens `/login` instead of home page
- add HTMX spinner for login page
- provide toast error notification if login is challenged (e.g., 2FA)
- Also enable tweet fetching in TweetDetail handler if tweet is missing or not scraped
- Improve some UI stuff w/ more styles
- Enable HTMX page swapping in some places instead of full page loads
