⬆️ 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/obiphylo/tree.md

@@ -0,0 +1,30 @@
+# `obiphylo` Package: Semantic Description
+
+The `obiphylo` package provides a minimal yet expressive data structure and utilities for representing **phylogenetic trees** in Go.
+
+## Core Type: `PhyloNode`
+- Represents a node (taxon or internal branch point) in a phylogeny.
+- Fields:
+  - `Name`: Optional label (e.g., species name, OTU ID).
+  - `Children`: A map of child nodes to **branch lengths** (evolutionary distances).
+  - `Attributes`: A flexible key-value store for metadata (e.g., bootstrap support, posterior probability).
+
+## Key Functionalities
+- **Tree Construction**:
+  - `NewPhyloNode()`: Instantiates an empty node.
+  - `AddChild(child, distance)`: Appends a child with associated branch length (supports NaN for unlabeled branches).
+- **Metadata Access**:
+  - `SetAttribute(key, value)` / `GetAttribute(key)`: Enables extensible node annotation.
+  - Supports arbitrary types (via `any`), ideal for dynamic metadata.
+
+## Output: Newick Format
+- Recursive method `Newick(level int)` generates a **human-readable, standard phylogenetic tree string**:
+  - Properly indented for readability.
+  - Supports branch lengths (`:distance`) on edges (skips if `NaN`).
+  - Terminates with semicolon (`;`) at root level.
+- Designed for interoperability (e.g., export to tools like RAxML, FigTree).
+
+## Design Notes
+- Lightweight and dependency-free.
+- Uses Go’s idiomatic maps for efficient child lookup (O(1) average).
+- Recursive Newick generation ensures correct nesting and formatting.