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/pushover.md

@@ -0,0 +1,25 @@
+# pushover
+
+Send notifications via the Pushover API.
+
+## Usage
+
+```bash
+pushover -T <token> -U <user> [-t title] [-p priority] message
+```
+
+Common options:
+
+- `-c <callback>` – callback URL
+- `-d <device>` – target device
+- `-s <sound>` – notification sound name
+- `-T <token>` – application token (or `PUSHOVER_TOKEN` env)
+- `-U <user>` – user key (or `PUSHOVER_USER` env)
+
+## Example
+
+```bash
+pushover -T $TOKEN -U $USER -t "Build" "Finished successfully"
+```
+
+<!-- vim: set ft=markdown spell spelllang=en_us cc=80 : -->