chore: add Makefile and Debian packaging

Makefile

@@ -0,0 +1,77 @@
+BINARY   := ezcoo-usb-control
+VERSION  ?= 0.1.0
+CMD      := ./cmd/$(BINARY)
+
+BUILD_DIR := build
+DIST_DIR  := dist
+
+DEB_TARGETS := arm64 armhf amd64
+
+.PHONY: build deb-all $(addprefix deb-,$(DEB_TARGETS)) clean deps prepare lint
+
+deps:
+	go mod tidy
+
+prepare: deps
+	go mod download
+	go generate ./...
+
+lint: prepare
+	gofmt -w -s .
+	goimports -w .
+	go vet ./...
+	golangci-lint run --color always
+
+build: prepare
+	mkdir -p $(BUILD_DIR)
+	go build -o $(BUILD_DIR)/$(BINARY) $(CMD)
+
+# ── Per-architecture .deb builder ─────────────────────────────────────────────
+# $(1) = Debian arch (arm64 / armhf / amd64)
+# $(2) = GOARCH       (arm64 / arm  / amd64)
+# $(3) = GOARM        (7 for armhf, empty otherwise)
+define make_deb
+	$(eval BIN     := $(BUILD_DIR)/$(BINARY)-$(1))
+	$(eval PKG_DIR := $(BUILD_DIR)/pkg-$(1))
+	$(eval DEB_OUT := $(DIST_DIR)/$(BINARY)_$(VERSION)_$(1).deb)
+	$(eval GO_ENV  := GOOS=linux GOARCH=$(2)$(if $(3), GOARM=$(3),))
+
+	mkdir -p $(BUILD_DIR) $(DIST_DIR)
+	$(GO_ENV) go build -o $(BIN) $(CMD)
+
+	rm -rf $(PKG_DIR)
+
+	install -D -m 0755 $(BIN) $(PKG_DIR)/usr/bin/$(BINARY)
+	install -D -m 0640 cmd/ezcoo-usb-control/config.example.yaml $(PKG_DIR)/etc/$(BINARY)/config.yaml
+	install -D -m 0644 packaging/systemd/$(BINARY).service $(PKG_DIR)/lib/systemd/system/$(BINARY).service
+
+	install -d $(PKG_DIR)/DEBIAN
+	sed -e 's/VERSION_PLACEHOLDER/$(VERSION)/' \
+	    -e 's/ARCH_PLACEHOLDER/$(1)/' \
+	    packaging/DEBIAN/control  > $(PKG_DIR)/DEBIAN/control
+	install -m 0644 packaging/DEBIAN/conffiles  $(PKG_DIR)/DEBIAN/conffiles
+	install -m 0755 packaging/DEBIAN/postinst   $(PKG_DIR)/DEBIAN/postinst
+	install -m 0755 packaging/DEBIAN/prerm      $(PKG_DIR)/DEBIAN/prerm
+	install -m 0755 packaging/DEBIAN/postrm     $(PKG_DIR)/DEBIAN/postrm
+
+	dpkg-deb --build --root-owner-group $(PKG_DIR) $(DEB_OUT)
+	rm -rf $(PKG_DIR)
+	@echo "→ $(DEB_OUT)"
+endef
+
+deb-arm64:
+	$(call make_deb,arm64,arm64,)
+
+deb-armhf:
+	$(call make_deb,armhf,arm,7)
+
+deb-amd64:
+	$(call make_deb,amd64,amd64,)
+
+deb-all: $(addprefix deb-,$(DEB_TARGETS))
+	@echo ""
+	@echo "Built packages:"
+	@ls -lh $(DIST_DIR)/$(BINARY)_$(VERSION)_*.deb
+
+clean:
+	rm -rf $(BUILD_DIR) $(DIST_DIR)

packaging/DEBIAN/conffiles

@@ -0,0 +1 @@
+/etc/ezcoo-usb-control/config.yaml

packaging/DEBIAN/control

@@ -0,0 +1,14 @@
+Package: ezcoo-usb-control
+Version: VERSION_PLACEHOLDER
+Architecture: ARCH_PLACEHOLDER
+Maintainer: Oleksandr Berezovskyi <claude.ai@berezovskyi.dev>
+Depends: adduser
+Recommends: mosquitto-clients
+Description: MQTT bridge for EZCOO HDMI matrix switches
+ Controls an EZCOO EZ-MX42HAS-ARC (4-in 2-out) HDMI matrix via USB-UART
+ and exposes it to Home Assistant as two select entities through MQTT
+ auto-discovery.
+ .
+ Communicates with the matrix using the EZCOO ASCII serial protocol and
+ periodically polls routing state to detect external changes (front panel,
+ IR remote).

packaging/DEBIAN/postinst

@@ -0,0 +1,33 @@
+#!/bin/sh
+set -e
+
+case "$1" in
+    configure)
+        # Create system user if it doesn't exist.
+        if ! id -u ezcoo > /dev/null 2>&1; then
+            adduser --system --no-create-home --shell /usr/sbin/nologin \
+                    --group --gecos "EZCOO HDMI matrix bridge" ezcoo
+        fi
+
+        # Ensure the user is in the dialout group for serial access.
+        if getent group dialout > /dev/null 2>&1; then
+            adduser ezcoo dialout
+        fi
+
+        # Lock down the config directory so only ezcoo can read credentials.
+        chown -R root:ezcoo /etc/ezcoo-usb-control
+        chmod 750 /etc/ezcoo-usb-control
+        chmod 640 /etc/ezcoo-usb-control/config.yaml
+        ;;
+esac
+
+if [ -d /run/systemd/system ]; then
+    systemctl daemon-reload
+    systemctl enable ezcoo-usb-control.service
+    # Only start automatically on fresh installs, not upgrades.
+    if [ "$1" = "configure" ] && [ -z "$2" ]; then
+        systemctl start ezcoo-usb-control.service || true
+    fi
+fi
+
+#DEBHELPER#

packaging/DEBIAN/postrm

@@ -0,0 +1,19 @@
+#!/bin/sh
+set -e
+
+case "$1" in
+    purge)
+        rm -rf /etc/ezcoo-usb-control
+        if id -u ezcoo > /dev/null 2>&1; then
+            deluser --quiet ezcoo || true
+        fi
+        if getent group ezcoo > /dev/null 2>&1; then
+            delgroup --quiet ezcoo || true
+        fi
+        if [ -d /run/systemd/system ]; then
+            systemctl daemon-reload
+        fi
+        ;;
+esac
+
+#DEBHELPER#

packaging/DEBIAN/prerm

@@ -0,0 +1,13 @@
+#!/bin/sh
+set -e
+
+case "$1" in
+    remove|upgrade|deconfigure)
+        if [ -d /run/systemd/system ]; then
+            systemctl stop ezcoo-usb-control.service || true
+            systemctl disable ezcoo-usb-control.service || true
+        fi
+        ;;
+esac
+
+#DEBHELPER#

packaging/systemd/ezcoo-usb-control.service

@@ -0,0 +1,26 @@
+[Unit]
+Description=EZCOO HDMI Matrix MQTT bridge
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStart=/usr/bin/ezcoo-usb-control --config /etc/ezcoo-usb-control/config.yaml
+Restart=on-failure
+RestartSec=5
+User=ezcoo
+SupplementaryGroups=dialout
+
+# Allow reading an optional environment file for secrets.
+# EnvironmentFile=-/etc/ezcoo-usb-control/env
+
+# Hardening
+NoNewPrivileges=true
+ProtectSystem=strict
+ProtectHome=true
+PrivateTmp=true
+DeviceAllow=char-ttyUSB rw
+DeviceAllow=char-ttyACM rw
+
+[Install]
+WantedBy=multi-user.target