### Added
- File logging to `/var/log/ha-backup.log`. Each line has a full date and time,
and the file is appended to on every run.
- New `LOG_FILE` setting in `home_assistant_backup.conf`. Set it to a custom
path, or to `"none"` to disable file logging.
- `ssh`/`scp` error output is also written to the log file.
- Deletions of old local backups are now logged.
### Changed
- All console messages now go through the same logger, so remote cleanup,
notification failures and config validation errors appear in the log too.
- If the log file can't be opened (for example, no write permission to
`/var/log`), a warning is printed and the backup continues without file logging.
- The terminal progress bar stays on the console only and is not written to the log.
Rewrite home_assistant_backup.sh as a single Go binary that reads the
existing home_assistant_backup.conf unchanged.
- Create a backup over SSH, scp it locally, and prune old backups both
on the HA host (when free space is low) and locally
- Send ntfy and Discord notifications at the same points as the script
- Drop the jq and yq dependencies: parse `ha backups --raw-json` and
`ha backup new --raw-json` in Go, falling back to `slug:` line parsing
- Add timestamped progress output, a heartbeat while HA builds the
backup, and live size/percent/speed reporting during the copy
- Build the Discord payload with json.Marshal and validate backup slugs
before using them in remote commands
- Abort with a notification if the remote disk-space check fails
- Add -config and -version flags
- Build with CGO_ENABLED=0 for a static binary that runs on older glibc
phil