Link each child issue to its paired GitHub security alert

[miroslavpojer]

Feature Description

When the alerts-to-issue workflow creates a child (per-alert) issue, embed a direct link to the originating GitHub security alert in the issue body. This makes it trivial to navigate from a tracking issue back to the raw alert in the Security tab without manual searching.

Problem / Opportunity

Currently, child issues contain information derived from a GitHub alert (e.g. severity, rule, description), but there is no direct hyperlink back to the alert itself. Developers and security reviewers must manually locate the alert in the repository's Security → Code scanning / Dependabot alerts view to see the full alert detail, dismiss options, or check fix availability. This creates unnecessary friction.

Acceptance Criteria

1. Each child issue body contains a clearly labelled section (e.g. ## GitHub Alert) with a direct URL to the paired GitHub security alert.
2. The link is formatted as a clickable Markdown hyperlink, e.g. View alert on GitHub.
3. Existing child issues that are updated/re-synced also get the link added if it is missing.

Proposed Solution

Add the new field to host link to issue paired alert.

Dependencies / Related

No response

Additional Context

No response