feat: Runner image variants, CI improvements (#306)

## Description

Next step would be having full DE environment variant I guess? I'll see
later if it's doable in this PR or if I'll do separate one for keeping
things small and manageable for once 😅

- Added easily doable variants for runners, with simple CI build matrix.
- Added playsite in CI builds finally.
- Some CI formatting and naming fixes.
- Removed PR full runner builds as they kept failing due to lack of disk
space on GH runner.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* New dedicated runner images for Steam, Heroic, and Minecraft plus a
common runtime and builder images.
* **Chores**
* CI/workflow reorganization to build and publish more runner variants
and base images.
* Installer and package tweaks (package manager flags, CUDA enablement)
and updated build tooling.
* Unified startup to use a constructed launch command; removed two
default environment exports.
  * Added container ignore patterns.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: DatCaptainHorse <DatCaptainHorse@users.noreply.github.com>

packages/scripts/entrypoint_nestri.sh

@@ -106,12 +106,9 @@ start_compositor() {
     kill_if_running "${COMPOSITOR_PID:-}" "compositor"
     kill_if_running "${APP_PID:-}" "application"
 
-    # Set default values only if variables are unset (not empty)
-    if [[ -z "${NESTRI_LAUNCH_CMD+x}" ]]; then
-        NESTRI_LAUNCH_CMD="dbus-launch steam -tenfoot -cef-force-gpu"
-    fi
+    # Set default compositor if unset
     if [[ -z "${NESTRI_LAUNCH_COMPOSITOR+x}" ]]; then
-        NESTRI_LAUNCH_COMPOSITOR="gamescope --backend wayland --force-grab-cursor -g -f --rt --mangoapp -W ${WIDTH} -H ${HEIGHT} -r ${FRAMERATE:-60}"
+        NESTRI_LAUNCH_COMPOSITOR="gamescope --backend wayland --force-grab-cursor -g -f --rt -W ${WIDTH} -H ${HEIGHT} -r ${FRAMERATE:-60}"
     fi
 
     # If PRELOAD_SHIM_arch's are set and exist, set LD_PRELOAD for 32/64-bit apps
@@ -121,6 +118,16 @@ start_compositor() {
         log "Using LD_PRELOAD shim(s)"
     fi
 
+    # Configure launch cmd with dbus if set
+    local launch_cmd=""
+    if [[ -n "${NESTRI_LAUNCH_CMD+x}" ]]; then
+        if $do_ld_preload; then
+            launch_cmd="LD_PRELOAD='/usr/\$LIB/libvimputti_shim.so' dbus-launch $NESTRI_LAUNCH_CMD"
+        else
+            launch_cmd="dbus-launch $NESTRI_LAUNCH_CMD"
+        fi
+    fi
+
     # Launch compositor if configured
     if [[ -n "${NESTRI_LAUNCH_COMPOSITOR}" ]]; then
         local compositor_cmd="$NESTRI_LAUNCH_COMPOSITOR"
@@ -129,17 +136,12 @@ start_compositor() {
         # Check if this is a gamescope command
         if [[ "$compositor_cmd" == *"gamescope"* ]]; then
             is_gamescope=true
-            if [[ -n "$NESTRI_LAUNCH_CMD" ]] && [[ "$compositor_cmd" != *" -- "* ]]; then
-                # If steam in launch command, enable gamescope integration via -e
-                if [[ "$NESTRI_LAUNCH_CMD" == *"steam"* ]]; then
-                    compositor_cmd+=" -e"
-                fi
-                # If ld_preload is true, add env with LD_PRELOAD
-                if $do_ld_preload; then
-                    compositor_cmd+=" -- env LD_PRELOAD='/usr/\$LIB/libvimputti_shim.so' bash -c $(printf %q "$NESTRI_LAUNCH_CMD")"
-                else
-                    compositor_cmd+=" -- bash -c $(printf %q "$NESTRI_LAUNCH_CMD")"
+            if [[ -n "$launch_cmd" ]] && [[ "$compositor_cmd" != *" -- "* ]]; then
+                # If steam in launch command, enable gamescope integration via -e and enable mangohud
+                if [[ "$launch_cmd" == *"steam"* ]]; then
+                    compositor_cmd+=" --mangoapp -e"
                 fi
+                compositor_cmd+=" -- bash -c $(printf %q "$launch_cmd")"
             fi
         fi
 
@@ -185,9 +187,9 @@ start_compositor() {
                     WAYLAND_DISPLAY=wayland-0 wlr-randr --output "$OUTPUT_NAME" --custom-mode "$WIDTH"x"$HEIGHT"
                     log "Patched resolution with wlr-randr"
 
-                    if [[ -n "${NESTRI_LAUNCH_CMD}" ]]; then
-                        log "Starting application: $NESTRI_LAUNCH_CMD"
-                        WAYLAND_DISPLAY="$COMPOSITOR_SOCKET" /bin/bash -c "$NESTRI_LAUNCH_CMD" &
+                    if [[ -n "$launch_cmd" ]]; then
+                        log "Starting application: $launch_cmd"
+                        WAYLAND_DISPLAY="$COMPOSITOR_SOCKET" bash -c "$launch_cmd" &
                         APP_PID=$!
                     fi
                 else
@@ -200,9 +202,9 @@ start_compositor() {
         log "Warning: Compositor socket not found after 15 seconds ($COMPOSITOR_SOCKET)"
     else
         # Launch standalone application if no compositor
-        if [[ -n "${NESTRI_LAUNCH_CMD}" ]]; then
-            log "Starting application: $NESTRI_LAUNCH_CMD"
-            WAYLAND_DISPLAY=wayland-1 /bin/bash -c "$NESTRI_LAUNCH_CMD" &
+        if [[ -n "$launch_cmd" ]]; then
+            log "Starting standalone application: $launch_cmd"
+            WAYLAND_DISPLAY=wayland-1 bash -c "$launch_cmd" &
             APP_PID=$!
         else
             log "No compositor or application configured"