Add AMD FSR3 framegen interface probe and CI validation

rebuild.sh

@@ -22,8 +22,27 @@ ensure_fsr2_sdk() {
     }
 }
 
+ensure_fidelityfx_sdk() {
+    local sdk_dir="extern/FidelityFX-SDK"
+    local sdk_header="$sdk_dir/sdk/include/FidelityFX/host/ffx_frameinterpolation.h"
+    local sdk_ref="v1.1.4"
+    if [ -f "$sdk_header" ]; then
+        return
+    fi
+    if ! command -v git >/dev/null 2>&1; then
+        echo "Warning: git not found; cannot auto-fetch AMD FidelityFX SDK."
+        return
+    fi
+    echo "Fetching AMD FidelityFX SDK ($sdk_ref) into $sdk_dir ..."
+    mkdir -p extern
+    git clone --depth 1 --branch "$sdk_ref" https://github.com/GPUOpen-LibrariesAndSDKs/FidelityFX-SDK.git "$sdk_dir" || {
+        echo "Warning: failed to clone AMD FidelityFX SDK. FSR3 framegen extern will be unavailable."
+    }
+}
+
 echo "Clean rebuilding wowee..."
 ensure_fsr2_sdk
+ensure_fidelityfx_sdk
 
 # Remove build directory completely
 if [ -d "build" ]; then