2 new endpoints:
- POST /portfolio/cluster - t-SNE + KMeans clustering by return
similarity. Maps stocks to 2D coordinates with cluster labels.
- POST /portfolio/similar - find most/least similar stocks by
return correlation against a target symbol.
Implementation:
- sklearn TSNE (method=exact) + KMeans with auto n_clusters
- Jitter handling for identical returns edge case
- 33 new tests (17 service unit + 16 route integration)
- All 503 tests passing
4915f1bae4