Mount Steam Runtime in bwrap container

Mount Steam Runtime explicitly in bwrap container. This is necessary
because the installation can exist under one of the blacklisted root
directories (unlikely, but possible). We already made sure of this for
Proton, but forgot to do the same for Steam Runtime.

Fixes #471

Author: Matoking

CHANGELOG.md

@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [Unreleased]
 ### Fixed
  - Fix Steam installation being prompted twice when using `protontricks-launch`
+ - Fix Steam Runtime crash if it was installed under a blacklisted root directory (eg. `/run/<path>` instead of `/run/media/<path>`)
 
 ## [1.14.0] - 2026-02-22
 ### Added

src/protontricks/data/scripts/bwrap_launcher.sh

@@ -35,7 +35,7 @@ BLACKLISTED_ROOT_DIRS=(
 )
 
 ADDITIONAL_MOUNT_DIRS=(
-    /run/media "$PROTON_PATH" "$WINEPREFIX"
+    /run/media "$PROTON_PATH" "$WINEPREFIX" "$STEAM_RUNTIME_PATH"
 )
 
 mount_dirs=()