Treat empty remote dest path as home directory

scp's "host:" (no path after the colon) means the remote home
directory, reusing the source's basename. resolve_dest_paths only
recognized a directory target via a trailing '/', so an empty path
fell through and was used literally as the filename, producing an
empty --dest-final and hanging the remote --server --recv.

src/naming.rs

@@ -81,10 +81,11 @@ pub fn resolve_dest_paths(
     effective_compress: bool,
     partial_ext: &str,
 ) -> DestPaths {
-    // DEST may name a directory (trailing '/') -- in that case reuse the
+    // DEST may name a directory (trailing '/', or empty as in scp's
+    // "host:" meaning the remote home directory) -- in that case reuse the
     // source's logical basename underneath it. Otherwise DEST names the file
     // directly.
-    let dest_logical = if dest_path.ends_with('/') {
+    let dest_logical = if dest_path.is_empty() || dest_path.ends_with('/') {
         let base = Path::new(&source_stripped.logical)
             .file_name()
             .map(|n| n.to_string_lossy().to_string())
@@ -240,6 +241,16 @@ mod tests {
         assert_eq!(d.final_path, "/out/cap.pcap");
     }
 
+    #[test]
+    fn dest_paths_empty_target_is_home_dir() {
+        // scp-style "host:" (empty remote path) means the remote home
+        // directory -- reuse the source's basename, don't leave it empty.
+        let src = strip_name("cap.pcap.partial", "partial");
+        let d = resolve_dest_paths("", &src, false, "partial");
+        assert_eq!(d.final_path, "cap.pcap");
+        assert_eq!(d.temp_path, "cap.pcap.partial");
+    }
+
     #[test]
     fn size_parsing() {
         assert_eq!(parse_size("256k").unwrap(), 256 * 1024);