feat: Add MultiViewKMeans estimator for multi-feature clustering

Implements MultiViewKMeans estimator with:
- Per-view divergences (different distance measures for each view)
- Per-view weights (importance weighting)
- Combine strategies: "weighted" (default), "max", "min"
- ViewSpec case class for view configuration
- Full persistence support (save/load)
- 21 comprehensive tests

Use cases:
- Document clustering (content + metadata + citations)
- Image clustering (pixels + captions + metadata)
- Multi-modal data (text + audio + video features)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: derrickburns

CHANGELOG.md

@@ -28,13 +28,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Single entry point for all 8 Bregman divergences
   - Auto-selection based on data sparsity with `forSparsity()` method
   - Canonical divergence name constants in `KernelFactory.Divergence`
-- **Test suites for new components** (129 new tests, 737 total):
+- **MultiViewKMeans estimator** for clustering data with multiple feature representations (21 tests)
+  - Per-view divergences (different distance measures for each view)
+  - Per-view weights (importance weighting)
+  - Combine strategies: "weighted" (default), "max", "min"
+  - `ViewSpec` case class for view configuration
+  - Full persistence support (save/load)
+- **Test suites for new components** (150 new tests, 758 total):
   - OutlierDetectionSuite: 16 tests for distance-based and trimmed outlier detection
   - SparseBregmanKernelSuite: 28 tests for sparse-optimized SE, KL, L1, Spherical kernels
   - ConstraintsSuite: 30 tests for must-link/cannot-link constraints and penalty computation
   - ConstrainedKMeansSuite: 17 tests for semi-supervised clustering with soft/hard constraints
   - RobustKMeansSuite: 17 tests for robust clustering with outlier handling and persistence
   - SparseKMeansSuite: 21 tests for sparse clustering with auto-detection and persistence
+  - MultiViewKMeansSuite: 21 tests for multi-view clustering with persistence
 
 ### Architecture
 - Moved AcceleratedSEAssignment to `strategies/impl/` subpackage for better organization

ROADMAP.md

@@ -25,7 +25,7 @@ Goal: land the highest-demand capabilities and supporting docs.
 
 - ~~**Robust Bregman clustering + outlier handling** (3.11 / 5.8)~~ — **DONE**: `RobustKMeans` with trim/noise_cluster/m_estimator modes, outlier scoring, persistence.
 - ~~**Sparse Bregman clustering** (3.12)~~ — **DONE**: `SparseKMeans` estimator with auto-sparsity detection, `KernelFactory` for unified kernel creation.
-- **Multi-view clustering** (3.13 / 5.9) — implement `MultiViewKMeans` with shared `MultiViewAssignment`, per-view weights/divergences.
+- ~~**Multi-view clustering** (3.13 / 5.9)~~ — **DONE**: `MultiViewKMeans` estimator with per-view weights/divergences, combine strategies (weighted/max/min), `ViewSpec` configuration.
 - **Docs & notebooks** (6.1) — quick-start notebook, divergence selection guide, X-Means auto-k demo, soft-clustering interpretation examples.
 
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@@ -57,7 +57,7 @@ These frameworks unblock multiple roadmap items; prefer delivering them before d
 | Component | Priority | Enables | Notes |
 |-----------|----------|---------|-------|
 | ~~Outlier Detection (5.8)~~ | ~~P1~~ | ~~Robust Bregman clustering (3.11)~~ | **DONE**: Trim/noise-cluster strategies, scoring column |
-| Multi-View (5.9) | P1 | Multi-view clustering (3.13) | View specs, weights, divergences |
+| ~~Multi-View (5.9)~~ | ~~P1~~ | ~~Multi-view clustering (3.13)~~ | **DONE**: ViewSpec, per-view weights/divergences, combine strategies |
 | Sequence Kernels (5.10) | P2 | Time-series clustering (3.15) | DTW/shape kernels, barycenters |
 | Consensus (5.11) | P2 | Ensemble clustering (3.16) | Base generator + co-association |
 | Federated (5.12) | P2 | Federated Bregman clustering (3.17) | Secure aggregation, optional DP |
@@ -87,6 +87,7 @@ These frameworks unblock multiple roadmap items; prefer delivering them before d
 | 2025-12-15 | Use phased delivery for accelerations and new iterators | Keep CI stable while iterating |
 | 2025-12-16 | Created `KernelFactory` for unified kernel creation | Single API for dense/sparse kernels, reduces duplication |
 | 2025-12-16 | Moved assignment strategies to `impl/` subpackage | Better organization, backward-compatible via type aliases |
+| 2025-12-16 | Implemented `MultiViewKMeans` with ViewSpec configuration | Per-view divergences/weights, weighted/max/min combine strategies |
 
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