Add skill authoring commands

[dbpolito]

Ticket

SKIPPED

Description

Adds dedicated skill authoring commands so users can create and refine Agent Skills through the bundled command surface, with matching configuration and documentation across the workspace.

Checklist

Skill authoring commands

• Add /skill/create and /skill/optimize as bundled commands for focused skill creation and optimization workflows
• Add shared skill-authoring guidance so both commands follow the same scoped authoring and validation rules

Bundled configuration

• Enable the new commands and shared component across core, schema, and adapter configuration surfaces
• Extend command config coverage so the bundled templates and command metadata stay in sync

Docs and product surfaces

• Document the new commands and shared component in the reference docs and getting-started guides
• Update homepage and command showcase content so the new skill workflows appear in product-facing surfaces

Validation

• Verify that bundled command configuration still exposes the expected command and component set
• Confirm that the generated command templates include the shared skill-authoring guidance
• Check that docs and showcase surfaces present the new skill workflows consistently

[kompassdev]

★★★★☆

The command templates, shared component, config surfaces, schema, test coverage, and generated output are all consistent and correct. One sync gap to address:

packages/web/src/content/docs/docs/reference/commands/index.mdx still groups /skill/create, /skill/optimize, and /learn under Core, but CommandShowcase.astro now separates them into a Guidelines group while the remaining former-Core commands live under Workflow. Per the AGENTS.md requirement to keep user-facing docs and showcase surfaces in sync when commands are added or renamed, the docs reference page should reflect the same grouping taxonomy as the showcase.

[kompassdev]

★★★★☆

The command templates, shared component, config surfaces, schema, test coverage, generated output, and showcase are all consistent and correct. One remaining sync gap from the prior review:

The Groups list in the docs reference page now correctly separates Workflow and Guidelines, matching the showcase taxonomy, but the detailed section heading ## Workflow Commands still groups /learn, /skill/create, and /skill/optimize under a single "Workflow Commands" heading instead of splitting into separate ## Workflow Commands and ## Guidelines sections to match. This is a continuation of the same surface-sync issue the prior review flagged — the summary list was fixed but the section structure beneath it wasn't updated to match.