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).

.github/workflows/fuzz.yml

@@ -21,6 +21,7 @@ jobs:
                 working-directory: rust/fuzz
         steps:
             - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
+            - run: sudo apt-get update && sudo apt-get install -y libasound2-dev
             - run: rustup toolchain install nightly --profile minimal
             - run: cargo +nightly install cargo-fuzz --locked
             - run: cargo +nightly fuzz run ${{ matrix.target }} -- -max_total_time=120 -rss_limit_mb=2048