Add implement-spec Claude Code skill for automated spec-to-PR workflow #38

Summary

Add a project-level Claude Code skill (/implement-spec) that automates the full workflow from a spec file to a merged-ready PR.

Skill location

.claude/skills/implement-spec/SKILL.md

What the skill does

When invoked as /implement-spec specs/SOME_SPEC.md, Claude will:

1. Read the spec — injected into context via !cat preprocessing
2. Create a GitHub issue — title from spec Overview, body is the full spec
3. Create a feature branch — kebab-case, e.g. add-credit-card-faker
4. Implement the spec — YAML data, Java class, Faker.java registration, test class
5. Run tests — verifies the feature and checks for regressions
6. Commit — references the issue number (closes #N)
7. Create a PR — via existing ./create-pr.sh

Skill design

• disable-model-invocation: true — must be invoked manually (has side-effects)
• allowed-tools: Bash, Read, Write, Edit, Glob, Grep — pre-granted for the full workflow
• argument-hint: <path/to/SPEC.md> — shown in autocomplete
• Uses !cat "$ARGUMENTS" preprocessing to inline the spec before Claude responds