chore: point every in-tree reference at ai-job-search-dev/ai-job-search (#776)

The repository is moving from the MadsLorentzen personal account to the
ai-job-search-dev organization. GitHub redirects the old slug, but the
upstream-watch guard compares github.repository against the literal slug
and would start running the fork-only triage job on upstream itself, and
the upstream-check tool and its tests pin the slug too. README, CONTRIBUTING,
SECURITY, SETUP, the CI workflow, the issue-template config and the
CHANGELOG links follow.

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

.github/ISSUE_TEMPLATE/config.yml

@@ -1,7 +1,7 @@
 blank_issues_enabled: true
 contact_links:
   - name: Filing from a personalized fork? Read this first
-    url: https://github.com/MadsLorentzen/ai-job-search/blob/master/SETUP.md#2-fork-and-clone
+    url: https://github.com/ai-job-search-dev/ai-job-search/blob/master/SETUP.md#2-fork-and-clone
     about: >-
       The gh CLI in a fork clone targets THIS public repo by default. Personal
       application tracking, evaluations, and incident logs belong in your own