feat: add bats tests, docs (#139)

* fix(test): ensure bats file list uses xargs

* docs(readme): use yarn for testing instructions

* fix(test): ensure pipelines fail properly

* docs(alias): fix table header

---------

Signed-off-by: Ismo Vuorinen <ismo@ivuorinen.net>

local/bin/t.md

@@ -0,0 +1,23 @@
+# t
+
+Launch or switch to a tmux session based on a directory selected with
+`fzf`. Inspired by scripts from ThePrimeagen and Jess Archer.
+
+## Usage
+
+```bash
+t
+```
+
+Environment variables:
+
+- `T_ROOT` – base directory to search (default: `~/Code`)
+- `T_MAX_DEPTH` – recursion depth for directory search
+
+### Example
+
+```bash
+T_ROOT=~/projects t
+```
+
+<!-- vim: set ft=markdown spell spelllang=en_us cc=80 : -->