Fix SLR download failures and CMake rebuild detection

Replace SHA256SUMS verification with Content-Length check for SLR
downloads. Valve's CDN frequently serves stale SHA256SUMS that don't
match the current archive, causing persistent checksum mismatches.

Fix CMake DEPENDS for nak_ffi to glob all .rs sources instead of
hardcoding a few files — previously changes to slr.rs (and most other
Rust files) were silently ignored by ninja.

Also wrap prefix init and runtime commands through SLR pressure-vessel
container, and expose Proton install directories to the container.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/src/src/protonlauncher.cpp b/src/src/protonlauncher.cpp
index 3c279fa..c6fc545 100644
--- a/src/src/protonlauncher.cpp
+++ b/src/src/protonlauncher.cpp
@@ -463,9 +463,9 @@ bool ProtonLauncher::launchWithProton(qint64& pid) const
       // Build: [wrappers] run_script [--filesystem=...] -- proton_script protonArgs
       QStringList slrArgs;
 
-      // Expose the game directory (and its FUSE-mounted Data/) to the
-      // pressure-vessel container.  Without this, the container's mount
-      // namespace may not see FUSE mounts on the host.
+      // Expose host directories to the pressure-vessel container.
+      // Without --filesystem= flags, the container's mount namespace
+      // may not see FUSE mounts or system-installed Proton paths.
       if (!m_binary.isEmpty()) {
         const QString gameDir = QFileInfo(m_binary).absolutePath();
         slrArgs << QStringLiteral("--filesystem=%1").arg(gameDir);
@@ -473,6 +473,13 @@ bool ProtonLauncher::launchWithProton(qint64& pid) const
       if (!m_prefixPath.isEmpty()) {
         slrArgs << QStringLiteral("--filesystem=%1").arg(m_prefixPath);
       }
+      // Expose the Proton installation directory — needed for
+      // system-installed Protons (e.g. /usr/share/steam/compatibilitytools.d/)
+      // whose files may not be visible inside the container by default.
+      {
+        const QString protonDir = QFileInfo(protonScript).absolutePath();
+        slrArgs << QStringLiteral("--filesystem=%1").arg(protonDir);
+      }
 
       slrArgs << "--" << protonScript << protonArgs;
       wrapProgram(m_wrapperCommands, runScript, slrArgs, program, arguments);