v0.5.1

Fix: Correct skill invocation names

All cross-skill references used wrong action suffixes (e.g., code-reviewer:review,
git-committer:commit, proj-ideatender:analyze) that caused Unknown skill errors
at runtime. Fixed to use the actual fully qualified skill names from each SKILL.md
frontmatter.

Changes

• code-reviewer:review → code-reviewer:code-reviewer
• git-committer:commit → git-committer:git-committer
• proj-ideatender:analyze → proj-ideatender:proj-ideatender
• Added cycle-repeat clarification to code-partner Phase 2
• Bumped code-partner, git-committer, and spec-writer to v0.5.1