feat(rdp): remote audio and a shared folder redirected as a drive

- Audio: the RDPSND channel with IronRDP's cpal playback backend (PCM;
  Opus left out to avoid another native library). On by default for new
  RDP profiles. Building now needs the ALSA headers on Linux
  (libasound2-dev), added to CI, release and fuzz jobs and the build docs.
- Shared folder (Linux/macOS): one local folder appears on the remote
  desktop as a drive. IronRDP's native backend joins server paths onto
  the share unchecked, so it is wrapped in ConfinedDrive: create, list
  and rename paths with '..' components, NUL bytes, or that resolve
  through a symlink outside the share are refused (ACCESS_DENIED);
  tests cover the escapes.

Verified against xrdp (with FUSE): the remote read the shared file, and
writes, mkdir and rename landed in the local folder. Not verified:
audio playback (the test container has no sound module), and xrdp lists
the drive as 'ignored' and can't list its directories (an IronRDP/xrdp
naming and listing mismatch, fixed upstream for the name).

docs/build-and-release.md

@@ -17,7 +17,7 @@ The toolchain is pinned in `rust/rust-toolchain.toml`; `rustup` installs it on f
 
   ```bash
   sudo apt-get install -y build-essential pkg-config libxkbcommon-dev libgl1-mesa-dev \
-    libx11-dev libxcursor-dev libxrandr-dev libxi-dev libwayland-dev libgtk-3-dev zip
+    libx11-dev libxcursor-dev libxrandr-dev libxi-dev libwayland-dev libgtk-3-dev libasound2-dev zip
   ```
 
 - **macOS:** Xcode command-line tools (`xcode-select --install`).