Remove latest-sdk from docs (not implemented)

The latest-sdk link relation was documented but never added to
llms.json - it wasn't considered valuable enough. Removed from:
- dotnet-releases/SKILL.md
- navigation-flows/SKILL.md

🤖 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

@@ -53,7 +53,6 @@ From `_embedded.latest_patches[]._links`:
 | Relation | Target |
 | -------- | ------ |
 | `release-manifest` | manifest.json (OS, breaking changes) |
-| `latest-sdk` | SDK index |
 | `latest-security` | Last security patch |
 
 From `llms.json._links`:

release-notes/skills/navigation-flows/SKILL.md

@@ -29,7 +29,7 @@ llms.json
             │       ├─► supported-os-json ─► distros
             │       └─► os-packages-json ─► packages
             │
-            └─► _links.latest-sdk ─► sdk/index.json ─► DONE
+            └─► _links.latest-security ─► last security patch
 ```
 
 ## Flow 2: CVE Queries (2-N fetches)
@@ -68,7 +68,6 @@ From llms.json:
 From latest_patches[]:
   release-major ───────────► X.0/index.json (patches, timeline)
   release-manifest ────────► manifest.json (reference data)
-  latest-sdk ──────────────► sdk/index.json (SDK bands)
   latest-security ─────────► last security patch
 
 From manifest.json: