Update CI to use map generation instead of test map fixture

Changes:
- Removed 'Install test map fixture' step (test_fixtures/ was deleted)
- Updated script.txt to use map generation approach
- MapName: sb_initial_blank_10x8 (no file on disk)
- Added [MAPOPTIONS] with new_map_x=10, new_map_y=8
- Added [MODOPTIONS] with mapseed=1

This matches test-smoke.sh approach. CI will now test actual map
generation code path to see if it works with full Spring + xvfb.

Author: claude

.github/workflows/smoke-test.yml

@@ -71,27 +71,26 @@ jobs:
           cat test-data/springsettings.cfg
           echo "Sound subsystem disabled via Sound = 0 config"
 
-      - name: Install test map fixture
+      - name: Create Spring script.txt for map generation
         run: |
-          # Use bundled minimal test map (downloads are blocked with 403)
-          # The test map is a minimal 2x2 Spring map with proper .smf format
-          cp -r test_fixtures/minimal_test_map.sdd games/
-          ls -lah games/minimal_test_map.sdd/
-          echo "Test map fixture installed"
-
-      - name: Create Spring script.txt
-        run: |
-          # Use bundled minimal test map
-          echo "Using test map: TestMinimal2x2"
+          # Use map generation (no map files needed)
+          # SpringBoard generates terrain at runtime based on MAPOPTIONS
+          echo "Using map generation: sb_initial_blank_10x8"
           cat > script.txt << 'SCRIPTEND'
           [GAME]
           {
             GameType=SpringBoard Core;
-            MapName=TestMinimal2x2;
+            MapName=sb_initial_blank_10x8;
             IsHost=1;
             MyPlayerName=TestPlayer;
+            [MAPOPTIONS]
+            {
+              new_map_x=10;
+              new_map_y=8;
+            }
             [MODOPTIONS]
             {
+              mapseed=1;
             }
             [PLAYER0]
             {