Add whats-new skill for release highlights queries

New skill for "What's new in .NET X?" and "Release highlights?" queries.
Documents path to manifest.json links:
- whats-new-rendered → Microsoft Learn overview
- release-blog-rendered → DevBlogs announcement
- compatibility / compatibility-rendered → breaking changes (cross-ref)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: richlander

release-notes/skills/dotnet-releases/SKILL.md

@@ -19,6 +19,7 @@ Fetch when your query matches. **Core Rules apply to all.**
 | ----- | ---------- | --- |
 | cve-queries | "Critical CVEs in .NET 8?" "CVEs fixed last 3 months?" | <https://raw.githubusercontent.com/dotnet/core/refs/heads/release-index/release-notes/skills/cve-queries/SKILL.md> |
 | breaking-changes | "Breaking changes in .NET 10?" "Migration impact?" | <https://raw.githubusercontent.com/dotnet/core/refs/heads/release-index/release-notes/skills/breaking-changes/SKILL.md> |
+| whats-new | "What's new in .NET 10?" "Release highlights?" | <https://raw.githubusercontent.com/dotnet/core/refs/heads/release-index/release-notes/skills/whats-new/SKILL.md> |
 | version-eol | "When does .NET 8 go EOL?" "What versions are supported?" | <https://raw.githubusercontent.com/dotnet/core/refs/heads/release-index/release-notes/skills/version-eol/SKILL.md> |
 | os-support | "Does .NET 10 support Ubuntu 24.04?" "What packages needed?" | <https://raw.githubusercontent.com/dotnet/core/refs/heads/release-index/release-notes/skills/os-support/SKILL.md> |
 | navigation-flows | Multi-hop query, unsure which links to follow | <https://raw.githubusercontent.com/dotnet/core/refs/heads/release-index/release-notes/skills/navigation-flows/SKILL.md> |

release-notes/skills/whats-new/SKILL.md

@@ -0,0 +1,71 @@
+---
+name: whats-new
+description: Release highlights, new features, and announcements for .NET versions
+---
+
+# What's New Queries
+
+## Stop Criteria
+
+**STOP when you have the manifest.json.** It contains links to "What's New" docs and release blog posts. These are `-rendered` links (HTML pages)—fetch only if you need to summarize content.
+
+## Quick Answers (from manifest.json)
+
+Once you have `manifest.json._links`:
+
+- What's new docs URL? → `whats-new-rendered.href`
+- Release announcement URL? → `release-blog-rendered.href`
+- Downloads page? → `downloads-rendered.href`
+
+## Navigation Flow (2 fetches for URLs, 3 to read content)
+
+```
+llms.json
+    │
+    └─► _embedded.latest_patches[] ─► _links["release-manifest"]
+            │
+            ▼
+        manifest.json
+            │
+            ├─► _links["whats-new-rendered"] ─► Microsoft Learn (HTML)
+            │
+            └─► _links["release-blog-rendered"] ─► DevBlogs announcement (HTML)
+```
+
+## Common Queries
+
+### What's new in .NET X? (2-3 fetches)
+
+1. `llms.json` → find version in `_embedded.latest_patches[]`
+2. Follow `_links["release-manifest"]` → manifest.json
+3. Return `whats-new-rendered.href` or fetch and summarize
+
+### Release announcement for .NET X? (2-3 fetches)
+
+Same path, use `release-blog-rendered.href`
+
+## Available Links
+
+| Relation | Content |
+|----------|---------|
+| `whats-new-rendered` | Microsoft Learn "What's New" overview |
+| `release-blog-rendered` | DevBlogs release announcement |
+| `compatibility` | Breaking changes JSON (see breaking-changes skill) |
+| `compatibility-rendered` | Breaking changes HTML view |
+| `downloads-rendered` | .NET download page |
+| `usage-markdown-rendered` | Runtime/SDK usage guidance |
+
+## Common Mistakes
+
+| Mistake | Why It's Wrong |
+|---------|----------------|
+| Looking for raw markdown | Only `-rendered` (HTML) versions exist for announcements |
+| Constructing docs.microsoft.com URLs | Follow `_links` from manifest |
+| Fetching HTML when URL is enough | If user just needs link, don't fetch the page |
+
+## Tips
+
+- `-rendered` links are HTML (human-friendly), not raw data
+- `whats-new-rendered` has comprehensive feature overview
+- `release-blog-rendered` has highlights and context
+- For LLM summarization, fetch the HTML and extract key points