Add verify-releases and update-release-graph skills (dotnet#10332)

* Add update-release-graph skill

Documents the workflow for regenerating the HAL+JSON release
information graph using the VersionIndex, ShipIndex, and LlmsIndex
generators from distroessed. Covers source data conventions,
graph topology, and validation steps.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add verify-releases skill for release link validation

New Copilot skill that validates .NET release data using dotnet-release
v0.5.0+ verify releases command. Checks URL liveness, SHA512 file hashes,
CDN latest.version files, and aka.ms redirect targets.

Includes:
- SKILL.md with full process documentation, commands, timing expectations,
  troubleshooting, and report template
- Reference example with actual verification output from all supported
  versions (8.0, 9.0, 10.0, 11.0)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add cve-enricher skill for CVE generation and enrichment

Describes how to use the dotnet-cve-enricher tool to synthesize, validate,
and enrich cve.json files in the release-notes timeline directory.

Covers:
- Synthesizing CVE records from releases.json + MSRC data
- Validating existing cve.json for data integrity
- Updating lookup dictionaries and CVSS/CNA data
- Agent usage with --json output mode

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Update skill install instructions for dotnet-release 1.1.0

Remove --version "0.*" workaround from all skill prerequisites now
that 1.1.0 is the latest version on the GitHub Packages feed.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Remove cve-enricher skill

The cve-enricher tool isn't ready yet. Remove the skill to keep
the PR focused on verify-releases and update-release-graph.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: richlander

.github/skills/update-distro-packages/SKILL.md

@@ -45,16 +45,14 @@ If not installed:
 
 ```bash
 dotnet tool install -g Dotnet.Release.Tools \
-  --add-source https://nuget.pkg.github.com/richlander/index.json \
-  --version "0.*"
+  --add-source https://nuget.pkg.github.com/richlander/index.json
 ```
 
 If already installed, update to latest:
 
 ```bash
 dotnet tool update -g Dotnet.Release.Tools \
-  --add-source https://nuget.pkg.github.com/richlander/index.json \
-  --version "0.*"
+  --add-source https://nuget.pkg.github.com/richlander/index.json
 ```
 
 ## Inputs

.github/skills/update-os-packages/SKILL.md

@@ -31,8 +31,7 @@ The `dotnet-release` tool must be installed. Packages are published to [GitHub P
 ```bash
 # GitHub Packages requires authentication — use a GitHub token (PAT or GITHUB_TOKEN)
 dotnet tool install -g Dotnet.Release.Tools \
-  --add-source https://nuget.pkg.github.com/richlander/index.json \
-  --version "0.*"
+  --add-source https://nuget.pkg.github.com/richlander/index.json
 
 # Verify
 dotnet-release --help