[codex] Add spread v2 image watermark payload mode

.github/workflows/python-engine.yml

@@ -31,7 +31,7 @@ jobs:
           dep = check_dependencies()
           assert dep['ok'], f'Missing deps: {dep}'
 
-          img = np.random.randint(0, 256, (800, 800, 3), dtype=np.uint8)
+          img = np.random.default_rng(7).integers(0, 256, (800, 800, 3), dtype=np.uint8)
 
           embedded = embed_watermark(
               img,
@@ -49,7 +49,26 @@ jobs:
               quality='balanced',
           )
           assert extracted['ok'], f'Extract failed: {extracted}'
-          assert extracted['wm'] == 'hello world', f'Roundtrip failed: {extracted}'
+          assert extracted['wm'].startswith('fp:'), f'Fingerprint roundtrip failed: {extracted}'
+          assert extracted.get('payloadMode') == 'fingerprint64', extracted
+
+          text16_embedded = embed_watermark(
+              img,
+              'hello world',
+              password=42,
+              quality='balanced',
+              payload_mode='text16',
+          )
+          assert text16_embedded['ok'], f'Text16 embed failed: {text16_embedded}'
+
+          text16_extracted = extract_watermark(
+              text16_embedded['image'],
+              password=42,
+              quality='balanced',
+              payload_mode='text16',
+          )
+          assert text16_extracted['ok'], f'Text16 extract failed: {text16_extracted}'
+          assert text16_extracted['wm'] == 'hello world', f'Text16 roundtrip failed: {text16_extracted}'
 
           print('All tests passed.')
 

blind_watermark/README.md

@@ -5,7 +5,7 @@ It is a heavily modified version of the original [blind_watermark](https://githu
 
 ## Modifications in LuminCrypt
 
-- **Adaptive Quality Profiles**: Dynamically adjusts Reed-Solomon error correction (`rs_nsym`) and block redundancy based on selected quality (invisible, balanced, robust).
+- **Adaptive Quality Profiles**: Dynamically adjusts Reed-Solomon error correction (`rs_nsym`) and block redundancy for the legacy engine, plus six neural visibility/robustness profiles (trace, faint, light, balanced, strong, robust). Low-visibility neural profiles use keyed Y-channel DCT spread-spectrum embedding to avoid visible grid or line patterns.
 - **Multi-scale Embedding & Extraction**: Embeds the watermark at multiple resolutions (e.g., 1.0x, 0.75x, 0.5x) to resist severe downscaling and platform compression.
 - **Enhanced Synchronization**: Uses a dual-ring, multi-peak template for better resistance against rotation, cropping, and aspect ratio changes.
 - **Edge Exclusion**: Avoids embedding watermarks in the outermost edges of the image where cropping is most likely to occur.
@@ -14,4 +14,4 @@ It is a heavily modified version of the original [blind_watermark](https://githu
 
 ## License
 
-The original code is licensed under the MIT License. See the `NOTICE` file in the root directory for full copyright and license details.
+The original code is licensed under the MIT License. See the `NOTICE` file in the root directory for full copyright and license details.