LR-IMP-CAMERA-COVERAGE: Sony ILCE-7CM2 ARW codings in the corpus (#697)

Issue #697 (ILCE-7CM2 lossless compressed M-size ARW "washed out" in 0.4
and 0.5) is the 512-vs-1024 YCbCr pedestal of #535 item 3, fixed on main
by 3100cc1a after v0.5.0. Measured on the reporter's file: 0.5.0 renders
the darkest half of the dusk scene +11 L* and blue against the camera
JPEG, with the lamplight turned white (mean dE 11.8); main is within
+3 L* (dE 8.9). Its darkest 0.1 % per channel sits at 1017/1020/1024,
confirming the 1024 pedestal on a fifth body.

- Corpus: two CC0 raw.pixls.us ILCE-7CM2 files, lossless L and the
  compressed "M-size" coding, which is Bayer at 4736x3132 with black 512
  (only the lossless M/S codings are YCbCr), so a size-based pedestal
  rule would break it.
- Tests: corpus_sony_a7cm2_codings (model, layout, levels, crop, as-shot
  gains, header/full agreement) and both files in the #535 data-floor
  test.
- docs/parity.md: the ILCE-7CM2 verification on the Sony coverage row.

xtask/src/main.rs

@@ -371,6 +371,18 @@ const RAW_SAMPLES: &[(&str, &str, &str)] = &[
         "https://raw.pixls.us/data/Sony/ILCE-7CR/DSC00798.ARW",
         "f5096e8fbccf0842c8a57763cabd2836608f019eb7fd54f7b22260c2f5bc4da5",
     ),
+    // ILCE-7CM2 (33 MP, issue #697): lossless compressed L, and the compressed "M-size" coding, which is Bayer at
+    // 4736×3132 with black 512 (only the lossless M/S codings are YCbCr with the 1024 pedestal)
+    (
+        "arw-sony-a7cm2-lossless-l.arw",
+        "https://raw.pixls.us/data/Sony/ILCE-7CM2/DSC02431.ARW",
+        "342d893bd71fd050c273df181e3039d3f12d88947b0662de5de5325c84cc449b",
+    ),
+    (
+        "arw-sony-a7cm2-compressed-m.arw",
+        "https://raw.pixls.us/data/Sony/ILCE-7CM2/DSC02436.ARW",
+        "002c86d38a16b08a2438780728b4fda8efcc745fa6c26231dad6af67b383b11e",
+    ),
     // a dusk sky clipped in green behind a poplar: the clipped-highlight colour of issue #523
     (
         "arw-sony-a7rm4-14bit-compressed.arw",