Resolve template updates by semver for branch-tracked templates

[Ilyes512]

Summary

• Fix specs template update/upgrade treating a lower-numbered tag pushed on a later commit (e.g. 1.0.1 after the installed 1.1.0) as a newer version.
• Branch-tracked templates whose checkout sits exactly on a released semver tag now require a strictly-greater semver tag to report an update, matching tag-tracking behaviour; rolling branches keep branch-tip commit comparison.
• Determine the current version from the tag pointing exactly at HEAD (annotated tags dereferenced), not git-describe output whose -<n>-g<hash> suffix parses as a semver pre-release.
• Add tests (issue repro, higher-tag upgrade, non-semver fallback, semverTagAtCommit) and document the version-resolution rules under docs/.

Fixes #83.