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.rs

@@ -0,0 +1,5 @@
+fn main() {
+    let qr = qrcode::QrCode::new("unsandbox-qr-ok").unwrap();
+    let w = qr.width();
+    println!("QR:unsandbox-qr-ok:ROWS:{}", w);
+}