feat: add MediaPipe hand landmark support

[tarunbommawar27]

Before submitting

• Self-reviewed the code
• Updated documentation, follow [Google-style](https://google.github.io/styleguide/pyguide.html#383-functions-and-methods)
• Added docs entry for autogeneration (if new functions/classes)
• Added/updated tests
• All tests pass locally

Description

Adds support for MediaPipe hand landmarks in the key points module.

This PR adds a new Skeleton.HAND definition for MediaPipe's 21 hand landmarks and extends KeyPoints.from_mediapipe() to parse hand landmark outputs from both current and legacy MediaPipe result formats.

Type of Change

• ✨ New feature (non-breaking change which adds functionality)
• 🧪 Test update

Motivation and Context

MediaPipe hand landmarks contain 21 keypoints per hand. The existing Skeleton enum supported COCO, GHUM, and FaceMesh skeletons, but did not include a hand skeleton. This meant EdgeAnnotator could not automatically draw hand landmark connections.

KeyPoints.from_mediapipe() also handled pose and face landmarks, but did not handle hand landmarks. This PR adds support for both hand_landmarks and multi_hand_landmarks.

Closes #2170

Changes Made

• Added Skeleton.HAND with 21 vertices and 20 MediaPipe hand landmark edges

• Added automatic lookup support through existing SKELETONS_BY_VERTEX_COUNT and SKELETONS_BY_EDGE_COUNT

• Extended KeyPoints.from_mediapipe() to support:

  • hand_landmarks
  • multi_hand_landmarks

• Updated MediaPipe fake test helpers to support hand landmark test cases

• Added tests for the hand skeleton definition and MediaPipe hand landmark parsing

• Made MediaPipe confidence extraction robust by defaulting missing visibility values to 1.0

Testing

• I have tested this code locally
• I have added unit tests that prove my fix is effective or that my feature works
• All new and existing targeted tests pass

Commands run:

python -m uv run pre-commit run --files src/supervision/key_points/core.py src/supervision/key_points/skeletons.py tests/helpers.py tests/key_points/test_core.py tests/key_points/test_skeletons.py

python -m uv run pytest tests/key_points/test_core.py::test_from_mediapipe_input tests/key_points/test_skeletons.py tests/key_points/test_annotators.py -q

Result:

35 passed

Google Colab (optional)

Not applicable.

Screenshots/Videos (optional)

Not applicable.

Additional Notes

The skeleton edges use 1-based indexing to match the existing EdgeAnnotator behavior, which subtracts 1 before indexing into keypoint arrays.

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 79%. Comparing base (fb02e5c) to head (d154217).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #2283   +/-   ##
=======================================
  Coverage       79%     79%           
=======================================
  Files           66      66           
  Lines         8567    8569    +2     
=======================================
+ Hits          6726    6732    +6     
+ Misses        1841    1837    -4     

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