Update docs for recent feature additions (#65)

* Update docs to reflect recent feature additions

- Add skill edit command section to commands reference
- Document --tags on create, --tag filter on list/search, --force on install
- Add tags field to skill format spec (frontmatter table + example)
- Document stylistic lint hints and parse warnings in validation reference
- Fix Go version requirement from 1.23+ to 1.25+
- Remove completed skill update item from AGENTS.md roadmap

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Add missing --scope flag to skill create docs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Merge pull request #18 from devrimcavusoglu/rename/scribe-to-skern

Rename project from scribe to skern