feat: initial Go project scaffold with build/test/release pipeline

- Go module: github.com/netcell-it/deklarix
- cmd/server/main.go: HTTP entry point with /health endpoint
- scripts/build.sh: cross-compile amd64 + arm64
- scripts/test.sh: go vet + race tests + build-check
- scripts/release.sh: full release flow (test → build → tag → push)
- packaging/DEBIAN: .deb control template
- design/enterprise.css: enterprise design system from enconf
- CLAUDE.md: complete build/test/release documentation
- .claude/settings.local.json: Claude Code permissions

packaging/DEBIAN/control.tmpl

@@ -0,0 +1,7 @@
+Package: deklarix
+Version: VERSION
+Architecture: ARCH
+Maintainer: NetCell IT <team@netcell-it.de>
+Description: Deklarix — deklarix.de / deklarix.com
+ Deklarix Software Package.
+Depends: