Add build recipe

Justfile

@@ -1,13 +1,25 @@
 default:
     @just --list --unsorted
 
-# build firmware
-build:
-    echo "Building firmware..."
+build := ".build"
+out := "firmware"
 
-# clear build cache
+# build firmware
+build board *args:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    BUILD="{{build}}/{{board}}"
+    echo "Building firmware..."
+    west build -d "$BUILD" -s zmk/app -b {{board}} {{args}} -- -DZMK_CONFIG="{{absolute_path('config')}}"
+    if [[ -f "$BUILD/zephyr/zmk.uf2" ]]; then
+        mkdir -p {{out}} && cp "$BUILD/zephyr/zmk.uf2" "{{out}}/{{board}}.uf2"
+    else
+        mkdir -p {{out}} && cp "$BUILD/zephyr/zmk.bin" "{{out}}/{{board}}.bin"
+    fi
+
+# clear build cache and artifacts
 clean:
-    rm -rf build
+    rm -rf {{build}} {{out}}
 
 # list all build targets
 list: