Enhancement: output should include Go version and runtime OS/arch

[Congregalis]

What

./transblog --version currently prints version/commit/build_time only. When users report bugs, we usually need Go version + OS/arch to reproduce packaging/runtime issues.

Current

transblog version=dev commit=none build_time=unknown

Proposed

Extend version output to include:

• go_version (via runtime.Version())
• os/arch (via runtime.GOOS/runtime.GOARCH)

Example:

transblog version=v1.0.0 commit=abc123 build_time=... go=go1.24.1 os=darwin arch=arm64

Acceptance criteria

• --version prints these fields
• Add a unit test for version.String() (or new helper)
• Ensure GoReleaser ldflags still work