feat(deploy): l4d2-game.slice + l4d2-build.slice with 100:1 weight ratio

Flat top-level slices. Game wins under contention; build still gets
the box when uncontended. Referenced by left4me-server@.service and
the script-sandbox systemd-run invocation.

deploy/files/usr/local/lib/systemd/system/l4d2-build.slice

@@ -0,0 +1,7 @@
+[Unit]
+Description=left4me script-sandbox build slice
+Before=slices.target
+
+[Slice]
+CPUWeight=10
+IOWeight=10

deploy/files/usr/local/lib/systemd/system/l4d2-game.slice

@@ -0,0 +1,7 @@
+[Unit]
+Description=left4me game-server slice
+Before=slices.target
+
+[Slice]
+CPUWeight=1000
+IOWeight=1000

deploy/tests/test_deploy_artifacts.py

@@ -9,6 +9,8 @@ DEPLOY = ROOT / "deploy"
 
 WEB_UNIT = DEPLOY / "files/usr/local/lib/systemd/system/left4me-web.service"
 SERVER_UNIT = DEPLOY / "files/usr/local/lib/systemd/system/left4me-server@.service"
+GAME_SLICE = DEPLOY / "files/usr/local/lib/systemd/system/l4d2-game.slice"
+BUILD_SLICE = DEPLOY / "files/usr/local/lib/systemd/system/l4d2-build.slice"
 GLOBAL_REFRESH_SERVICE = DEPLOY / "files/usr/local/lib/systemd/system/left4me-refresh-global-overlays.service"
 GLOBAL_REFRESH_TIMER = DEPLOY / "files/usr/local/lib/systemd/system/left4me-refresh-global-overlays.timer"
 SANDBOX_UNIT_DIR = DEPLOY / "files/usr/local/lib/systemd/system"
@@ -110,6 +112,22 @@ def test_server_unit_contains_perf_baseline_directives():
     assert "LogRateLimitIntervalSec=0" in unit
 
 
+def test_l4d2_game_slice_exists_with_high_weights():
+    assert GAME_SLICE.is_file()
+    text = GAME_SLICE.read_text()
+    assert "[Slice]" in text
+    assert "CPUWeight=1000" in text
+    assert "IOWeight=1000" in text
+
+
+def test_l4d2_build_slice_exists_with_low_weights():
+    assert BUILD_SLICE.is_file()
+    text = BUILD_SLICE.read_text()
+    assert "[Slice]" in text
+    assert "CPUWeight=10" in text
+    assert "IOWeight=10" in text
+
+
 def _fake_command(tmp_path, command_name):
     marker = tmp_path / f"{command_name}.args"
     command = tmp_path / command_name