Logfmt and syslog formats silently treated as JSON — data corruption #499

Summary

The config allows `format: logfmt` and `format: syslog` (valid `Format` enum variants), but `pipeline_v2.rs` falls through to the default arm which treats them as JSON lines. Since logfmt/syslog lines are not valid JSON, the scanner produces empty rows or malformed data with no error or warning.

Proposed fix

Either:

• Reject these formats at config validation time until they're implemented
• Or add logfmt/syslog parsers

```rust
Format::Logfmt | Format::Syslog => {
return Err(io::Error::new(
io::ErrorKind::Unsupported,
format!("format {:?} is not yet implemented", input_cfg.format),
));
}
```

Labels

bug, config