- Add APIToken field to Credentials struct with omitempty JSON tag
- Implement GetAPIToken() method with persistent token storage
- Add SaveRefreshToken() helper to preserve API tokens during OAuth
- Implement --api CLI flag to use API token instead of OAuth
- Validate empty refresh tokens and skip refresh if invalid
- Update README with API token usage documentation
DownloadVideo already handles the Panopto Login.aspx canvas auth form
correctly through its multi-step form submission logic. The real fix for
ExternalUrl Panopto folder links was the URL normalization (List.aspx?folderID=
→ List.aspx#folderID="...") already in DownloadVideo.
Remove DownloadExternalPanoptoURL (dead code) and all debug prints.
Update README with -vo flag documentation.
