update implement-spec skill to support no-argument invocation and improve cleanup-branch #48

Overview

Update implement-spec skill to support no-argument invocation (using current git changes), and update cleanup-branch skill to use safer git fetch/switch commands.

Changes

cleanup-branch/SKILL.md

• Replace git checkout master && git pull with git fetch --all --prune --jobs=10 followed by git switch master && git pull
• Safer: git fetch is non-destructive; git switch is the modern preferred command over git checkout for branch switching

implement-spec/SKILL.md

• Update argument-hint from <path/to/SPEC.md> to [path/to/SPEC.md] (square brackets = optional)
• Update description to mention no-argument mode
• When invoked with no argument, fall back to git diff HEAD; git status --short as the spec content
• Update Step 2 issue creation: use --body-file in both cases (spec file and no-arg mode)
• Generalize branch naming guidance to "feature being implemented" rather than "spec's content"