feat(cmd): add --version, wired to the release tag via ldflags (#49)

`--version` errored with `unknown flag` — the binary had no build-time
version to print. Set cobra's rootCmd.Version (which registers
--version/-v for free) from a package var, injected at release time via
goreleaser ldflags. Dev builds report "dev".

Matches the pattern shipped in withings-export-cli#44.

New minor flag, no behavior change to any existing command.


Claude-Session: https://claude.ai/code/session_012MvqxTC64Z9EEDewCUbNNo

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: DTTerastar

.goreleaser.yml

@@ -16,6 +16,7 @@ builds:
         goarch: arm64
     ldflags:
       - -s -w
+      - -X github.com/quantcli/crono-export-cli/cmd.version=v{{ .Version }}
 
 archives:
   - formats:

cmd/root.go

@@ -8,9 +8,15 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// version is overwritten at release time via
+// -ldflags "-X github.com/quantcli/crono-export-cli/cmd.version=v1.1.0".
+// Setting rootCmd.Version below makes cobra register --version for free.
+var version = "dev"
+
 var rootCmd = &cobra.Command{
-	Use:   "crono-export",
-	Short: "Export Cronometer nutrition, biometrics, and food log data",
+	Use:     "crono-export",
+	Short:   "Export Cronometer nutrition, biometrics, and food log data",
+	Version: version,
 	Long: `crono-export reads your personal Cronometer data via the same export
 endpoints the web app uses and prints it on stdout.  Default output is
 narrow, fitdown-style markdown; pass --format json for the full