refactor: move webapp files to tests/plots to avoid code duplication

Move app.py, README.md, and requirements.txt from visualization/ into
tests/plots/ so they share _utils.py with the existing plotters. Update
the deploy workflow to point at tests/plots/.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: KhusPatel4450

.github/workflows/deploy-visualization.yml

@@ -4,7 +4,7 @@ on:
   push:
     branches: [main]
     paths:
-      - visualization/**
+      - tests/plots/**
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -28,7 +28,7 @@ jobs:
           from huggingface_hub import HfApi
           api = HfApi(token=os.environ['HF_TOKEN'])
           api.upload_folder(
-              folder_path='visualization',
+              folder_path='tests/plots',
               repo_id='torchjd/interactive-plotter',
               repo_type='space',
           )

visualization/README.md tests/plots/README.mdvisualization/README.md renamed to tests/plots/README.md

@@ -15,7 +15,7 @@ license: mit
 Interactive visualization of gradient aggregation methods from [TorchJD](https://torchjd.org).
 
 Adjust the angle and length of each gradient vector and select aggregators to see how they combine
-the gradients. The green region shows the dual cone — any descent direction must lie inside it.
+the gradients. The green region shows the dual cone: the set of vectors with a non-negative inner product with each gradient.
 
 ## URL parameters