⬆️ 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/obistats/tdist.md

@@ -0,0 +1,30 @@
+# `obistats.TDist`: Student's *t*-Distribution Implementation
+
+This Go package provides a lightweight implementation of the **Student’s *t*-distribution**, commonly used in statistical inference (e.g., hypothesis testing, confidence intervals) when sample sizes are small or population variance is unknown.
+
+## Core Components
+
+- **`TDist` struct**:  
+  Represents a *t*-distribution parameterized by degrees of freedom `V`.
+
+- **`PDF(x)` method**:  
+  Computes the *probability density function* at point `x`, using:
+  $$
+    f(x) = \frac{\Gamma\left(\frac{V+1}{2}\right)}{\sqrt{V\pi} \, \Gamma\left(\frac{V}{2}\right)} 
+           \left(1 + \frac{x^2}{V} \right)^{-\frac{V+1}{2}}
+  $$
+  Leverages `lgamma` for numerical stability in Gamma function evaluation.
+
+- **`CDF(x)` method**:  
+  Computes the *cumulative distribution function*:
+  - Returns `0.5` at symmetry point (`x == 0`);
+  - Uses the **regularized incomplete beta function** `mathBetaInc` for `x > 0`;
+  - Exploits symmetry: `CDF(-x) = 1 − CDF(x)` for `x < 0`.
+
+- **`Bounds()` method**:  
+  Returns a practical truncation interval `[-4, 4]`, sufficient for most visualizations or numerical integration over the central mass of the distribution.
+
+## Dependencies & Notes
+
+- Relies on standard library `math` and custom/internal helpers (`lgamma`, `mathBetaInc`) — likely from a shared internal module.
+- Designed for performance and numerical robustness, suitable in statistical tooling or benchmark analysis (as suggested by the `obistats` package name and reference to a bench-related repo).