feat: RDP profiles, sessions and viewer

- Protocol::Rdp with RdpConfig (domain, password mode, certificate
  policy, TLS-only fallback, fixed or tab-sized resolution, SOCKS5/HTTP
  proxy, SSH tunnel); migration 008 adds rdp_config and drops the
  protocol CHECK constraint so new protocols no longer need a rebuild.
- Session manager: connect_rdp dials directly, via the shared proxy
  module (proxy password from the secret store) or an SSH tunnel; the
  server certificate goes through the known-hosts check (key type
  rdp-tls); a tab-sized desktop uses the tab's reported pixel size, and
  resizes wait until the server opens Display Control. Rejected NLA
  passwords count as auth failures, so a saved one is asked again.
- The VNC viewer becomes DesktopView for both protocols; a small adapter
  turns its keysyms and pointer masks into RDP scancodes, Unicode keys,
  buttons and wheel events. For RDP, Paste Clipboard types the text.
- Profile editor RDP section, Quick Connect, badges, docs.

Verified against xrdp in the app: logon, desktop, input, and connections
through SOCKS5 and HTTP CONNECT relays. Not verified here: Windows/NLA
servers, the SSH tunnel route, and Display Control resizing (xrdp
0.9.24 never opened the channel).

rust/core/src/clients/rdp.rs

@@ -209,6 +209,8 @@ impl Client {
         }
         .build();
         let mut input = Database::new();
+        // A resize waits here until the Display Control channel is open (it opens after logon).
+        let mut want_size: Option<(u16, u16)> = None;
         loop {
             let mut outputs = Vec::new();
             loop {
@@ -219,12 +221,7 @@ impl Client {
                             outputs.extend(stage.process_fastpath_input(&mut image, &events)?);
                         }
                     }
-                    Ok(Input::Resize(w, h)) => {
-                        let (w, h) = ironrdp::displaycontrol::pdu::MonitorLayoutEntry::adjust_display_size(w.into(), h.into());
-                        if let Some(frame) = stage.encode_resize(w, h, None, None) {
-                            outputs.push(ActiveStageOutput::ResponseFrame(frame?));
-                        }
-                    }
+                    Ok(Input::Resize(w, h)) => want_size = Some((w, h)).filter(|&s| s != (image.width(), image.height())),
                     Ok(Input::Close) | Err(mpsc::TryRecvError::Disconnected) => {
                         for o in stage.graceful_shutdown()? {
                             if let ActiveStageOutput::ResponseFrame(f) = o {
@@ -236,6 +233,13 @@ impl Client {
                     Err(mpsc::TryRecvError::Empty) => break,
                 }
             }
+            if let Some((w, h)) = want_size {
+                let (w, h) = ironrdp::displaycontrol::pdu::MonitorLayoutEntry::adjust_display_size(w.into(), h.into());
+                if let Some(frame) = stage.encode_resize(w, h, None, None) {
+                    outputs.push(ActiveStageOutput::ResponseFrame(frame?));
+                    want_size = None;
+                }
+            }
             match framed.read_pdu() {
                 Ok((action, payload)) => outputs.extend(stage.process(&mut image, action, &payload)?),
                 Err(e) if matches!(e.kind(), std::io::ErrorKind::WouldBlock | std::io::ErrorKind::TimedOut) => {}