docs: add frontmatter audit skill and refine topic guidelines

[IMinchev64]

Closes #

Checklist:

• check topic's TOC/menu and paragraph headings
• Include TOC topic labels in the topic content when it has a valuable update, is new, or is considered preview / beta
• link to other topics using ./page.mdx or ../relative/path.mdx (.mdx extension required)
• at the References section at the end of the topic add links to topics, samples, etc
• reference API documentation instead of adding a section with API

• use valid component names - [Data] Grid, IgxSelectComponent, <igx-combo>
• use spell checker tool (VS Code, Grammarly, Microsoft Editor)
• add inline code blocks for the names of classes / tags / properties
• add language descriptor for the code blocks
• check if links function by running the check-api/mdx npm commands
• check if sample is working and fully visible in the topic
• check if sample is working and fully visible in the StackBlitz
• check if code blocks match the code in StackBlitz demo
• add or update meaningful llms.description metadata and run npm run check:llms-metadata

• follow SEO guidelines to fill topic's metadata (SEO guidelines)

• do not resolve requested changes (leave that to the reviewer)

[Copilot]

Pull request overview

Adds a new dedicated skill for auditing/normalizing MDX YAML frontmatter, and updates the existing Ignite UI doc-topic authoring/audit guidance to incorporate Indigo.Design structure cues and new required section/asset expectations (e.g., ## Live Demo, Do/Don’t guidance image).

Changes:

• Introduces igniteui-topic-frontmatter as a canonical .ai skill plus Codex/Claude adapters.
• Refines igniteui-doc-topics workflow guidance to incorporate Indigo.Design structure mapping and explicit ## Live Demo requirements.
• Updates the house style and audit rubric to codify the ## Live Demo section contract and Do/Don’t guidance-image expectation.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
.codex/skills/igniteui-topic-frontmatter/SKILL.md	Adds Codex adapter pointing to the canonical frontmatter skill.
.claude/skills/igniteui-topic-frontmatter/SKILL.md	Adds Claude adapter pointing to the canonical frontmatter skill.
.ai/skills/igniteui-topic-frontmatter/SKILL.md	Adds the canonical frontmatter-only audit skill definition and rules.
.ai/skills/igniteui-doc-topics/SKILL.md	Updates author/audit workflow guidance (Indigo.Design mapping, Live Demo requirement, frontmatter-skill pointer).
.ai/skills/igniteui-doc-topics/references/house-style.md	Updates house style (imports, section order, Do/Don’t image guidance, Live Demo contract, Indigo.Design suggestions).
.ai/skills/igniteui-doc-topics/references/audit-rubric.md	Updates audit checks for ## Live Demo, Do/Don’t image/TODO requirement, and Indigo.Design-driven Usage opportunities.

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