Add implement-spec skill (in-progress) with its bucket docs

Add implement-spec skill (in-progress) with its bucket docs The skill itself takes a spec plus its tickets and drives them to one PR, reading the tickets as a task graph so implementer subagents can run concurrently across the ready frontier. Documentation duties for the in-progress bucket: - List it in skills/in-progress/README.md (flat list, name linked to its SKILL.md), the one entry every skill in a bucket must have. It stays out of the top-level README and .claude-plugin/plugin.json, and gets no docs page, as the bucket requires. - Add a changeset, so the release notes carry it. - Match the bucket's openai.yaml style in short_description: a short verb phrase, no closing period. Also ignore .claude, which holds settings.local.json and agent worktrees that should never be committed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

What happened

The commit introduces the 'implement-spec' skill along with initial documentation tasks to integrate it into the project’s skill set. Key documentation updates include listing it in the relevant README and adding a changeset for release notes.

Why it matters

This update enhances the capability of task management for developers using the skills framework, facilitating improved workflow efficiency through concurrent operations. Proper documentation promotes ease of access and onboarding for future contributors.

Sources