[Autoloop: build-tsikit-learn-scikit-learn-typescript-migration]

🤖 *This PR is maintained by Autoloop. Each accepted iteration adds a commit to this branch.*

## tsikit-learn — scikit-learn TypeScript Migration

**Program**: Build tsikit-learn: scikit-learn → TypeScript migration (Issue #5)
**Best Metric**: 15 `sklearn_features_ported`

### What's been implemented so far

**Phase 1 — Foundation:**
- `exceptions` — NotFittedError, ConvergenceWarning, ValueError
- `base` — BaseEstimator, ClassifierMixin, RegressorMixin, TransformerMixin, ClusterMixin
- `utils/extmath` — safeDot, gramMatrix, cholesky, rowNorms, matMul, transpose
- `utils/validation` — checkArray, checkXy, checkFeaturesConsistency
- `utils/multiclass` — typeOfTarget, uniqueLabels, classCount
- `utils/class_weight` — computeClassWeight, computeSampleWeight

**Phase 2 — Preprocessing & Metrics:**
- `preprocessing/StandardScaler` — Welford online mean/variance
- `preprocessing/MinMaxScaler` — feature_range scaling
- `preprocessing/LabelEncoder` — label encoding/decoding
- `preprocessing/Normalizer` — L1/L2/max normalization
- `metrics/regression` — MSE, MAE, R2, MAPE, explained_variance
- `metrics/classification` — accuracy, confusion_matrix, precision, recall, F1, log_loss
- `model_selection` — train_test_split, KFold, StratifiedKFold

**Phase 3 (new this iteration):**
- `linear_model/LinearRegression` — OLS via Cholesky decomposition (normal equations)
- `linear_model/Ridge` — L2-regularized least squares

### Infrastructure
- CI workflow (GitHub Actions with Bun)
- Comprehensive tests (60+ test cases)
- Interactive playground deployed to GitHub Pages

> Generated by [Autoloop](https://github.com/githubnext/tsikit-learn/actions/runs/25737555375/agentic_workflow) · ● 42.8M · [◷](https://github.com/search?q=repo%3Agithubnext%2Ftsikit-learn+%22gh-aw-workflow-id%3A+autoloop%22&type=pullrequests)
>
> To install this [agentic workflow](https://github.com/.github/workflows/blob/main/autoloop.md), run
> ```
> gh aw add .github/workflows/autoloop.md
> ```

---

> [!NOTE]
> This was originally intended as a pull request, but the git push operation failed.
>
> **Workflow Run:** [View run details and download bundle artifact](https://github.com/githubnext/tsikit-learn/actions/runs/25737555375)
>
> The bundle file is available in the `agent` artifact in the workflow run linked above.

To create a pull request with the changes:

```sh
# Download the artifact from the workflow run
gh run download 25737555375 -n agent -D /tmp/agent-25737555375

# Fetch the bundle into a local branch
git fetch /tmp/agent-25737555375/aw-autoloop-build-tsikit-learn-scikit-learn-typescript-migration.bundle refs/heads/autoloop/build-tsikit-learn-scikit-learn-typescript-migration:refs/heads/autoloop/build-tsikit-learn-scikit-learn-typescript-migration
git checkout autoloop/build-tsikit-learn-scikit-learn-typescript-migration

# Push the branch to origin
git push origin autoloop/build-tsikit-learn-scikit-learn-typescript-migration

# Create the pull request
gh pr create --title '[Autoloop: build-tsikit-learn-scikit-learn-typescript-migration]' --base main --head autoloop/build-tsikit-learn-scikit-learn-typescript-migration --repo githubnext/tsikit-learn
```