feat: update theme layout creation instructions

[jeffcarey]

References: Contributing guide · Skill authoring guide · Agent Skills spec

What changed

More strongly encourages the LLM to check whether the user wants to create a new LWC when creating a theme layout for Experience Cloud LWR sites.

Also removes some Roman numeral section annotations which are no longer present/needed.

Why

Without this update, it would often skip component creation which would yield a useless result.

Notes

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Skills

Manual checklist

Description quality

• Describes what the skill does and the expected output
• Includes relevant Salesforce domain keywords (Apex, LWC, SOQL, metadata types, etc.)
• Trigger phrases are specific enough for Vibes to select this skill reliably

Instructions

• Clear goal statement
• Step-by-step workflow
• Validation rules for generated output
• Defined output / artifact

Context efficiency

• Core instructions are concise — supporting material lives in templates/, examples/, or docs/ subdirectories
• No unnecessary background explanation in the body

Automated checks

Enforced by CI (npm run validate:skills) per the Agent Skills spec:

• Directory is one level deep, named in kebab-case (max 64 chars), contains SKILL.md
• Frontmatter name matches directory name; description is present, ≥ 20 words, ≤ 1024 characters, and includes trigger language
• Body is non-empty and under 500 lines
• Name uses gerund form ⚠ (warning — does not block merge)

[scottmo]

This is not just for theme layout tho. We also need it to add LWCs to regular pages.

[jeffcarey]

Oops-- will revert this part as the other update is the one that I think is more effective