Restore nvidia_config.sh's four test seams

The seams were applied, verified and measured, but never reached the
commit: cb1e8c53 shipped the file with its hardcoded /etc/X11,
/etc/profile and /home/$SUDO_USER paths. ci-mirror caught it by running
the suite from a clean checkout, where the tests read the REAL system
files -- the RenderAccel assertion failed against this machine's actual
xorg config, which says "disabled", and the pyroveil clone path came
back as /home/testuser rather than the tmpdir.

The local run passed only because a stale seamed copy was sitting in the
measurement worktree. Re-applied and grepped back immediately, which is
the documented rule for exactly this failure mode.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/superpowers/evidence/nvidia-config-seams-restore-2026-08-23.json

@@ -0,0 +1,41 @@
+{
+  "intent": "Restore the four test seams in nvidia_config.sh, which were verified and measured but did not reach the previous commit, so the committed suite read and wrote the real system files.",
+  "scope": [
+    "linux_configuration/scripts/single_use/fixes/lib/nvidia_config.sh",
+    "Non-goal: any change to the tests, which were already correct"
+  ],
+  "changes": [
+    "Re-applied the XORG_CONF, XORG_CONF_D, PROFILE_FILE and USER_HOME defaults at their assignment sites",
+    "Grepped the file for all four immediately after writing it, before running anything, because a silently-reverted edit is exactly what caused this"
+  ],
+  "verification": [
+    {
+      "command": "ci-mirror during git push",
+      "result": "fail",
+      "evidence": "'lib/tests suite failed: .../fixes/lib/tests/run_all.sh'. ci-mirror runs from a clean checkout of committed files, which is why it caught what the local run could not."
+    },
+    {
+      "command": "bash run_all.sh from a detached worktree at the previous commit",
+      "result": "fail",
+      "evidence": "EXIT 1 with 10 failures, including 'configure_xorg: enables RenderAccel (expected \"RenderAccel\" \"true\", got: # NVIDIA configuration with RenderAccel disabled)' -- the suite was reading this machine's real /etc/X11 config, and 'does not re-clone over a checkout' showed a clone path of /home/testuser/pyroveil rather than the tmpdir."
+    },
+    {
+      "command": "grep -n 'XORG_CONF:-|XORG_CONF_D:-|PROFILE_FILE:-|USER_HOME:-' nvidia_config.sh",
+      "result": "pass",
+      "evidence": "All four present at lines 26, 27, 60 and 85 after re-applying."
+    },
+    {
+      "command": "shellcheck + shfmt -l on nvidia_config.sh",
+      "result": "pass",
+      "evidence": "No findings, zero suppressions, no reformat pending."
+    }
+  ],
+  "risks": [
+    "The previous commit, cb1e8c53, is pushed and briefly had a suite that would write to the real /etc/X11/xorg.conf.d on any machine that ran it un-jailed. Nothing ran it in that window on this machine -- the real 20-nvidia.conf still carries its Jun 2025 mtime.",
+    "The local run passed against a stale seamed copy in the measurement worktree, which is why a clean-checkout run is now the check that matters before pushing."
+  ],
+  "rollback": [
+    "git revert the commit; nvidia_config.sh returns to hardcoded paths and the suite will fail again from a clean checkout",
+    "Re-run run_all.sh from a detached worktree to confirm the failure mode returns"
+  ]
+}

linux_configuration/scripts/single_use/fixes/lib/nvidia_config.sh

@@ -19,8 +19,12 @@ configure_xorg() {
 	echo "2. Configuring Xorg Settings..."
 	echo "==============================="
 
-	XORG_CONF="/etc/X11/xorg.conf"
-	XORG_CONF_D="/etc/X11/xorg.conf.d"
+	# These paths default to the real locations and are overridden only by
+	# the test harness. They are plain globals ASSIGNED here rather than read
+	# from the environment, so the default has to live at the assignment --
+	# an exported value alone would be overwritten on entry.
+	XORG_CONF="${XORG_CONF:-/etc/X11/xorg.conf}"
+	XORG_CONF_D="${XORG_CONF_D:-/etc/X11/xorg.conf.d}"
 	NVIDIA_CONF="$XORG_CONF_D/20-nvidia.conf"
 
 	# Create xorg.conf.d directory if it doesn't exist
@@ -53,7 +57,7 @@ configure_gcc_workaround() {
 	echo "3. Configuring GCC Mismatch Workaround..."
 	echo "=========================================="
 
-	local PROFILE_FILE="/etc/profile"
+	local PROFILE_FILE="${PROFILE_FILE:-/etc/profile}"
 	local timestamp
 	timestamp=$(date)
 	backup_file "$PROFILE_FILE"
@@ -78,7 +82,7 @@ install_pyroveil() {
 	echo "4. Pyroveil Setup for Mesh Shader Issues..."
 	echo "==========================================="
 
-	local user_home="/home/$SUDO_USER"
+	local user_home="${USER_HOME:-/home/$SUDO_USER}"
 	local pyroveil_dir="$user_home/pyroveil"
 
 	echo "Mesh shaders have poor support on NVIDIA drivers, causing issues in games"