feat: add version

[KazuCocoa]

No description provided.

[Copilot]

Pull request overview

Switches build version metadata from a git commit hash to a git tag, and enables the standard --version CLI flag in the resigner binary.

Changes:

• Replace GIT_COMMIT (via git describe --always --long --abbrev=12 --dirty) with GIT_TAG (via git describe --tags --always) in the Makefile and inject it as main.VCSRevision.
• Configure cli.VersionFlag with Name: "version" and a usage description so users can run --version, while avoiding a short alias that conflicts with -v verbose.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
Makefile	Replace commit-hash-based version with git-tag-based version injected via ldflags.
cmd/resigner/main.go	Enable --version flag with explicit name/usage instead of disabling the version flag entirely.

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