NS-21: fail CI if Godot logs SCRIPT ERROR during GdUnit discovery

GdUnit exits 0 when broken suites are skipped; grep log for parse/load errors.

.github/workflows/gdscript.yml

@@ -70,7 +70,22 @@ jobs:
             exit 1
           }
 
+      # GdUnit returns 0 if *executed* tests pass, even when Godot logs SCRIPT ERROR during suite
+      # discovery (broken test files are skipped). Fail the job if those errors appear in output.
       - name: GDUnit4 (headless)
         working-directory: client
+        shell: bash
         run: |
-          ~/godot/Godot_v4.6-stable_linux.x86_64 --headless --path . -s "$GDUNIT_CMDTOOL" --ignoreHeadlessMode -a res://test
+          set -euo pipefail
+          LOG="$(mktemp)"
+          trap 'rm -f "$LOG"' EXIT
+          ~/godot/Godot_v4.6-stable_linux.x86_64 --headless --path . -s "$GDUNIT_CMDTOOL" --ignoreHeadlessMode -a res://test 2>&1 | tee "$LOG"
+          godot_ec="${PIPESTATUS[0]}"
+          if [[ "$godot_ec" -ne 0 ]]; then
+            echo "::error::Godot/GdUnit exited with code ${godot_ec}"
+            exit "$godot_ec"
+          fi
+          if grep -E 'SCRIPT ERROR:|ERROR: Failed to load script' "$LOG"; then
+            echo "::error::Godot reported script parse/load errors (suites may have been skipped). Fix the test scripts."
+            exit 1
+          fi

client/README.md

@@ -100,6 +100,8 @@ godot --headless --path . -s res://addons/gdUnit4/bin/GdUnitCmdTool.gd --ignoreH
 
 On **Linux** (including GitHub Actions), the path must be **`gdUnit4`** with a capital **`U`**; `gdunit4` does not resolve.
 
+**CI:** The **GDScript** workflow fails the job if Godot prints **`SCRIPT ERROR:`** or **`ERROR: Failed to load script`** while running GdUnit. GdUnit alone can still exit **0** when a test file fails to parse (that suite is skipped); the workflow guards against that.
+
 **Scope:** Unit tests cover **`player.gd`**, **`position_authority_client.gd`**, and **`ground_pick.gd`** (walkable collider check). **`main.gd`**, full **`_input` / ray pick** flows, and scene wiring are **not** automated here—use manual checks above.
 
 **Reports:** GdUnit writes under **`reports/`** (gitignored); ignore locally generated HTML/XML when committing.