Add Gitea Actions CI and release workflows and deployment assets

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

deploy/build.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+# Builds hammerhead for every release platform and packs the archives into dist/.
+#
+#   deploy/build.sh [version]      version defaults to `git describe`
+#
+# Output:
+#   dist/bin/<os>_<arch>/hammerhead             the raw binaries (the Docker image uses the linux ones)
+#   dist/hammerhead_<version>_<os>_<arch>.tar.gz or .zip
+#   dist/SHA256SUMS
+#
+# Set TARGETS="linux/amd64 linux/arm64" to build fewer platforms.
+set -eu
+NAME=hammerhead
+cd "$(dirname "$0")/.."
+VERSION=${1:-$(git describe --tags --always 2>/dev/null || echo dev)}
+TARGETS=${TARGETS:-"linux/amd64 linux/arm64 linux/arm windows/amd64 darwin/amd64 darwin/arm64"}
+
+rm -rf dist
+mkdir -p dist/bin dist/stage
+for t in $TARGETS; do
+	os=${t%/*}
+	arch=${t#*/}
+	ext=""
+	[ "$os" = windows ] && ext=".exe"
+	out="dist/bin/${os}_${arch}"
+	mkdir -p "$out"
+	echo "building $NAME $VERSION for $os/$arch"
+	CGO_ENABLED=0 GOOS=$os GOARCH=$arch GOARM=7 \
+		go build -trimpath -ldflags "-s -w -X main.version=$VERSION" -o "$out/$NAME$ext" "./cmd/$NAME"
+
+	pkg="${NAME}_${VERSION}_${os}_${arch}"
+	stage="dist/stage/$pkg"
+	mkdir -p "$stage"
+	cp "$out/$NAME$ext" "$stage/"
+	for f in LICENSE README.md .env.example; do
+		[ -f "$f" ] && cp "$f" "$stage/"
+	done
+	if [ "$os" = linux ]; then
+		cp deploy/install.sh "deploy/$NAME.service" deploy/docker-compose.yml "$stage/"
+		chmod +x "$stage/install.sh"
+	fi
+	if [ "$os" = windows ] && command -v zip >/dev/null 2>&1; then
+		(cd dist/stage && zip -qr "../$pkg.zip" "$pkg")
+	else
+		tar -C dist/stage -czf "dist/$pkg.tar.gz" "$pkg"
+	fi
+done
+rm -rf dist/stage
+(cd dist && sha256sum $(ls | grep -E '\.(tar\.gz|zip)$') > SHA256SUMS)
+echo "done: $(ls dist | grep -cE '\.(tar\.gz|zip)$') archives in dist/"