feat(release): v0.4.0 foundations — ldflags version + goreleaser + CI Go 1.24

- Move version out of cmd/root.go hardcode into an ldflags-injected
  var. Makefile derives from 'git describe --tags --always --dirty';
  plain 'go build' / 'go run' get 'dev'. Release builds will get the
  tag via goreleaser.
- Add .goreleaser.yaml: multi-platform (linux/darwin/windows/freebsd ×
  amd64/arm64/arm) builds with SHA256 checksums, tar.gz/zip archives,
  forgejo release publishing. No GPG/S3 yet — deferred until a key is
  provisioned.
- Add .gitea/workflows/release.yml to run goreleaser on tag push.
  Uses built-in GITEA_TOKEN with override via RELEASE_TOKEN secret.
- Align CI Go version with go.mod (1.24). Previously CI ran 1.21,
  which would have silently missed any 1.22+ feature use.
- Move itchyny/gojq from indirect to direct (it's used in api.go).
  Drop stale x/sys v0.33.0 entry from go.sum.
- Ignore dist/ and bin/ in .gitignore.
- CHANGELOG: document v0.3.1 fix and Unreleased development changes.

cmd/root.go

@@ -14,12 +14,16 @@ import (
 var cfgFile string
 var jsonErrors bool
 
+// version is set at build time via -ldflags "-X .../cmd.version=...".
+// Defaults to "dev" for plain `go build` / `go run`.
+var version = "dev"
+
 var rootCmd = &cobra.Command{
 	Use:   "fgj",
 	Short: "Forgejo CLI tool - work seamlessly with Forgejo from the command line",
 	Long: `fgj is a command line tool for Forgejo instances (including Codeberg).
 It brings pull requests, issues, and other Forgejo concepts to the terminal.`,
-	Version:       "0.3.1",
+	Version:       version,
 	SilenceErrors: true,
 }