⬆️ version bump to v4.5

- Update obioptions.Version from "Release 4.4.29" to "/v/ Release v5"
- Update version.txt from 4.29 → .30
(automated by Makefile)

autodoc/docmd/pkg/obidist/dist_matrix.md

@@ -0,0 +1,28 @@
+# `obidist` Package: Efficient Symmetric Distance/Similarity Matrix Management
+
+The `*DistMatrix` type provides a memory-efficient, symmetric matrix implementation for distance or similarity data.
+
+- **Storage Strategy**: Only the upper triangle (i < j) is stored, reducing memory usage from *O(n²)* to *n(n−1)/2*.
+- **Diagonal Handling**: Diagonal entries are fixed (0.0 for distances, 1.0 for similarities); assignments to diagonal indices are silently ignored.
+- **Symmetry Guarantee**: `Get(i, j)` and `Set(i, j, v)` automatically handle both (i,j) and (j,i), ensuring consistency.
+
+## Constructors
+
+| Function | Description |
+|---------|-------------|
+| `NewDistMatrix(n)` / `WithLabels(labels)` | Creates *n×n* distance matrix (diag = 0). |
+| `NewSimilarityMatrix(n)` / `WithLabels(labels)` | Creates *n×n* similarity matrix (diag = 1). |
+
+## Core Operations
+
+- `Get(i, j)` / `Set(i, j, v)`: Access/update symmetric entries.
+- `Size() int`, `GetLabel(i)` / `SetLabel(i, label)`: Query/mutate element labels.
+- `Labels() []string`, `GetRow(i)` / `GetColumn(j)`: Retrieve full rows/columns (as copies).
+
+## Analysis Helpers
+
+- `MinDistance()`, `MaxDistance()` → `(value, i, j)` of the extremal off-diagonal entry.
+- `Copy() *DistMatrix`: Deep copy for immutability-safe operations.
+- `ToFullMatrix()` → `[][]float64`: Converts to dense representation (use sparingly).
+
+Designed for clustering, phylogenetics, or any domain requiring fast symmetric matrix access with minimal footprint.