⬆️ 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_test.md

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+# `obidist` Package: Semantic Feature Overview
+
+The `obidist` Go package provides two core data structures for managing **distance** and **similarity matrices**, with built-in guarantees suitable for scientific computing (e.g., clustering, phylogenetics). Key features include:
+
+- **`DistMatrix`**: A symmetric `n×n` matrix representing pairwise distances, where:
+  - Diagonal entries are *always* `0.0` (self-distance).
+  - Off-diagonals obey symmetry: `dist(i, j) == dist(j, i)`.
+  - Automatic enforcement via dedicated `Set()`/`Get()` methods.
+  
+- **`SimilarityMatrix`**: A symmetric matrix where:
+  - Diagonal entries are *always* `1.0`.
+  - Off-diagonals represent similarity scores (e.g., between `0` and `1`, though not enforced).
+  - Symmetry is similarly guaranteed.
+
+Both matrix types support:
+- **Optional labels**: Associate human-readable identifiers (e.g., sample names) with rows/columns.
+- **Safe bounds checking**: Panics on out-of-range access (tested via `defer/recover`).
+- **Deep copy support**: Ensures isolation between original and copied instances.
+- **Utility methods**:
+  - `MinDistance()` / `MaxDistance()`: Return extremal values and their indices.
+  - `GetRow(i)`: Retrieve a full row as a slice (symmetric copy).
+  - `ToFullMatrix()`: Export the matrix as an immutable 2D slice.
+
+Edge cases are rigorously handled:
+- Empty (`n=0`) and singleton (`n=1`) matrices return `(0.0, -1, -1)` for min/max.
+- Label mutations do not affect internal state via defensive copying.
+
+All behaviors are validated through comprehensive unit tests, emphasizing correctness and robustness.