Convert add-new-jit-ee-api prompt file to skills format

[Copilot]

Description

Converts .github/prompts/add-new-jit-ee-api.prompt.md to the modern Agent Skills format under .github/skills/. Skills are an open standard supported by Copilot coding agent, GitHub Copilot CLI, and VS Code, whereas prompt files are VS Code-specific.

Changes

• Created .github/skills/add-new-jit-ee-api/SKILL.md from prompts/add-new-jit-ee-api.prompt.md
• Removed .github/prompts/add-new-jit-ee-api.prompt.md
• Fixed duplicate file entries in add-new-jit-ee-api checklist

Format Migration

# Before (prompt file)
---
agent: 'agent'
tools: ['web/fetch', 'search/codebase', ...]
description: 'Description'
---

# After (skill file)
---
name: skill-name
description: Description
---

Content preserved; only frontmatter adapted to skill format.

Original prompt

Convert prompt-files @dotnet/runtime/files/.github/prompts into skills (https://docs.github.com/en/copilot/concepts/agents/about-agent-skills#creating-and-adding-skills). Skills are more modern way for that, and is open-standard while prompt-files seem to be VSCode only. Don't change the actual content too much unless necessary

---

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[EgorBo]

@copilot please revert docs.prompt.md, let's do it for jit-ee for now

[Copilot]

@copilot please revert docs.prompt.md, let's do it for jit-ee for now

Reverted docs.prompt.md in commit 1fa913c. Now only the add-new-jit-ee-api skill conversion is included.

[EgorBo]

PTAL @jakobbotsch cc @dotnet/jit-contrib - converted the prompt file (VSCode only, requires special convention) into a SKILL (open standard, all AI tools support)

[EgorBo]

/ba-g "Helix Queue Insights (preview) is stuck"