feat: add QR code functional tests across 41 languages

Native QR generation for each language's ecosystem:
- 27 languages use package manager QR libraries (qrcode, rqrcode, ZXing, etc.)
- 10 languages use C FFI to libqrencode (dlopen, ISO_C_BINDING, @cImport, critcl)
- 2 shell languages use qrencode CLI (native shell paradigm)
- 1 language (Prolog) uses C FFI with CLI fallback

Section 9 added to test-sdk.sh with get_qr_file() mapping and
QR:unsandbox-qr-ok:ROWS pattern validation across the hydra matrix.

test/qr.java

@@ -0,0 +1,11 @@
+import com.google.zxing.*;
+import com.google.zxing.common.BitMatrix;
+import com.google.zxing.qrcode.QRCodeWriter;
+
+public class qr {
+    public static void main(String[] args) throws Exception {
+        QRCodeWriter w = new QRCodeWriter();
+        BitMatrix m = w.encode("unsandbox-qr-ok", BarcodeFormat.QR_CODE, 0, 0);
+        System.out.println("QR:unsandbox-qr-ok:ROWS:" + m.getHeight());
+    }
+}