build: wire qmk.json build target and justfile recipes

justfile

@@ -2,6 +2,22 @@
 default:
     @just --list
 
+# compile moonlander matej keymap (artifact lands in firmware/)
+moonlander:
+    make -C qmk_upstream zsa/moonlander:matej QMK_USERSPACE={{justfile_directory()}}
+    mkdir -p firmware
+    mv -f zsa_moonlander_matej.bin firmware/
+    rm -f qmk_upstream/zsa_moonlander_matej.bin
+
+# compile + flash moonlander (polls until keyboard is in DFU mode; -d filter avoids the Cambridge DAC VID:PID collision)
+flash-moonlander: moonlander
+    until dfu-util -a 0 -d 0483:df11 -s 0x08000000:leave -D firmware/zsa_moonlander_matej.bin >/dev/null 2>&1; do sleep 0.5; done
+    @echo "flashed"
+
+# generate compile_commands.json for clangd / LSP
+compdb:
+    cd qmk_upstream && QMK_USERSPACE={{justfile_directory()}} qmk compile --compiledb -kb zsa/moonlander -km matej
+
 # format C/H files in place
 fmt:
     git ls-files '*.c' '*.h' | xargs --no-run-if-empty clang-format -i