fix(progress): rework transfer progress panel (#424)

Migrate the transfer progress UI to tuirealm 4, where the stdlib
`ProgressBar` widget was dropped, by rebuilding the dual-bar panel on
top of `Gauge`.

- Restore the unified two-bar look: the full bar (top) and partial bar
  (bottom) draw joined borders so they read as a single panel; a single
  file shows one fully-bordered bar.
- Redraw on every file boundary in the send/recv queue loops so the
  full bar's (N/total) counter advances even for small files that finish
  within one in-loop redraw interval.
- Track progress with a single `TransferProgress` (exact file count from
  the pre-scan, lazy partial/full computation) and consolidate the theme
  progress-bar fields.

Cargo.toml

@@ -67,7 +67,9 @@ remotefs = "0.3"
 remotefs-aws-s3 = "0.4"
 remotefs-kube = "0.4"
 remotefs-smb = { version = "0.3", optional = true }
-remotefs-ssh = { version = "0.8", default-features = false, features = ["russh"] }
+remotefs-ssh = { version = "0.8", default-features = false, features = [
+  "russh",
+] }
 remotefs-webdav = "0.2"
 rpassword = "7"
 self_update = { version = "0.42", default-features = false, features = [