refactor(sldd): unify skill entrypoint

[dearrudam]

This pull request significantly updates the documentation to clarify and enforce the repository's single-skill architecture, expand content and contribution guidelines, and provide more precise installation and usage instructions. The changes ensure that users and contributors understand the current structure, allowed content, and workflow of the SLDD skill, while removing legacy references and tightening repository policies.

Key changes include:

Repository structure and content policy

• Updated AGENTS.md to clarify that only one executable SLDD skill entrypoint (skills/sldd/SKILL.md) is permitted, with steps, templates, and schema files organized under dedicated subdirectories. Expanded the "Do" and "Don't" sections to enforce the single-skill model, progressive disclosure, and preservation of legacy resume compatibility. Added a new "Repository Content Policy" section specifying allowed file types and restricting runtime code and CI/CD changes.
• Updated repository scope: contributions are now limited to instructions, steps, templates, schema files, and documentation, explicitly prohibiting runtime application code and external API calls.

Installation and development instructions

• Revised README.md installation instructions to reflect the single-skill structure (removing references to multiple skills like sldd-*), and updated the development installation script section to clarify symlink/copy options and their effects.

Documentation and workflow clarity

• Updated the process flow and architecture sections in README.md to describe the single-skill layout, progressive disclosure, and the canonical journal storage under .sldd/specs/. Clarified the use of _spec-journal.json and legacy compatibility.
• Improved the SLDD process flow diagram and step descriptions to match the current workflow and naming conventions.

Terminology and consistency

• Standardized terminology throughout the documentation, using "skill" (singular) and updating descriptions to emphasize disciplined, specs-driven, single-skill development. [1] [2]

These changes help ensure that the repository remains focused, maintainable, and aligned with the intended SLDD methodology.

[omatheusmesmo]

What happen with the frontmatter?

https://platform.claude.com/docs/en/agents-and-tools/agent-skills/best-practices#skill-structure