fix: version not set correctly via ldflags

[Fuabioo]

Summary

• Fix version showing dev instead of actual tag when built via goreleaser
• Add SetVersion() function to update both cli.Version and rootCmd.Version
• Call SetVersion() from main() before Execute()

Problem

Running ch --version shows dev even when installed from goreleaser releases (e.g., via Homebrew tap).

Root Cause

The cobra command was initialized at package load time:

var rootCmd = &cobra.Command{
    Version: Version,  // Copies "dev" before main() runs
}

When main() later sets cli.Version = version, it's too late - rootCmd.Version already has "dev" baked in.

Solution

Added a SetVersion() function that updates both the exported Version variable AND the rootCmd.Version field.

Test Plan

• Verified with manual ldflags: go build -ldflags="-X main.version=1.2.3" -o ch ./cmd/ch && ./ch --version shows ch version 1.2.3
• Verified with full version info: shows ch version 1.2.3 (abc1234, 2026-01-06)
• Unit tests pass
• gofmt passes

🤖 Generated with Claude Code