add goreleaser configuration for binaries and deb/rpm packages

- build static binaries for linux, darwin and freebsd
- create deb and rpm packages that register gosh in /etc/shells
- publish releases to Gitea
- add --version flag, set at build time via ldflags

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

.goreleaser.yaml

@@ -0,0 +1,103 @@
+# yaml-language-server: $schema=https://goreleaser.com/static/schema.json
+# Release: git tag -a v0.1.0 -m "v0.1.0" && git push origin v0.1.0 && goreleaser release --clean
+# Local test (no publishing): goreleaser release --snapshot --clean
+version: 2
+
+project_name: gosh
+
+# GITHUB_TOKEN/GITLAB_TOKEN may also be set; always use Gitea.
+force_token: gitea
+
+before:
+  hooks:
+    - go mod tidy
+    - go test ./...
+
+builds:
+  - id: gosh
+    binary: gosh
+    main: .
+    env:
+      - CGO_ENABLED=0
+    flags:
+      - -trimpath
+    ldflags:
+      - -s -w -X main.version={{ .Version }}
+    goos:
+      - linux
+      - darwin
+      - freebsd
+    goarch:
+      - amd64
+      - arm64
+      - arm
+      - "386"
+    goarm:
+      - "7"
+    ignore:
+      - goos: darwin
+        goarch: "386"
+      - goos: darwin
+        goarch: arm
+    mod_timestamp: "{{ .CommitTimestamp }}"
+
+archives:
+  - id: gosh
+    formats: [tar.gz]
+    name_template: >-
+      {{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ with .Arm }}v{{ . }}{{ end }}
+    files:
+      - src: README.md
+        info:
+          mode: 0644
+
+nfpms:
+  - id: gosh
+    package_name: gosh
+    file_name_template: "{{ .ConventionalFileName }}"
+    ids: [gosh]
+    formats:
+      - deb
+      - rpm
+    vendor: Florian Walther
+    maintainer: Florian Walther <florian.walther@certainity.com>
+    homepage: https://gitea.scu.si/Florian.Walther/gosh
+    description: |-
+      gosh - a simple shell written in Go
+       Proof of concept with history, tab completion,
+       tilde and environment variable expansion.
+    license: ""
+    section: shells
+    priority: optional
+    bindir: /usr/bin
+    contents:
+      - src: README.md
+        dst: /usr/share/doc/gosh/README.md
+        file_info:
+          mode: 0644
+    scripts:
+      postinstall: packaging/scripts/postinstall.sh
+      postremove: packaging/scripts/postremove.sh
+
+checksum:
+  name_template: checksums.txt
+
+snapshot:
+  version_template: "{{ incpatch .Version }}-next"
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+
+# Repository is hosted on Gitea; requires GITEA_TOKEN in the environment.
+gitea_urls:
+  api: https://gitea.scu.si/api/v1
+  download: https://gitea.scu.si
+
+release:
+  gitea:
+    owner: Florian.Walther
+    name: gosh