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.kt

@@ -0,0 +1,8 @@
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.qrcode.QRCodeWriter
+
+fun main() {
+    val w = QRCodeWriter()
+    val m = w.encode("unsandbox-qr-ok", BarcodeFormat.QR_CODE, 0, 0)
+    println("QR:unsandbox-qr-ok:ROWS:${m.height}")
+}