feat(core): RDP client on IronRDP

clients::rdp connects over any caller-dialled TCP stream (direct, proxy
or SSH tunnel), upgrades to TLS and logs on with NLA (CredSSP/NTLM),
optionally falling back to TLS-only logon for servers without NLA such
as xrdp (credentials are passed so they log straight in). The server
certificate is pinned through a caller check on its SHA256 fingerprint
before any credentials are sent. The desktop decodes into the VNC
client's RGBA framebuffer; input (IronRDP's scancode/Unicode/mouse
operations), Display Control resizes and the deactivation-reactivation
sequence run on the session thread.

IronRDP's releases need three vendored patches (vendor/README.md):
picky and sspi with their RustCrypto release-candidate pins relaxed so
they share russh's stable versions (their own suites, 402 tests, pass
against them), and ironrdp-session with two unreleased upstream bitmap
fixes (#1486 stride, #1524 RDP6 orientation) without which xrdp desktops
render sheared.

Verified live against xrdp (scottyhardy/docker-remote-desktop): logon,
full desktop rendering, keyboard and mouse input.

rust/vendor/sspi/Info.plist

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>English</string>
+	<key>CFBundleExecutable</key>
+	<string></string>
+	<key>CFBundleIconFile</key>
+	<string></string>
+	<key>CFBundleIdentifier</key>
+	<string></string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundlePackageType</key>
+	<string>FMWK</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string></string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0.0.0</string>
+	<key>CSResourcesFileMapped</key>
+	<true/>
+	<key>MinimumOSVersion</key>
+	<string>12.1</string>
+</dict>
+</plist>