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>

.agents/skills/freehire-search/url-reference.md

@@ -138,7 +138,7 @@ points users to (`?q=<role>` scopes the counts). Example:
   serves HTML, which `cleanHtml` (`cli/src/helpers.ts`) strips into readable text.
   Search descriptions arrive already rendered by the API and are passed through
   verbatim — stripping them again would undo the Markdown structure.
-- Fetch sends `User-Agent: MadsLorentzen/ai-job-search/1.0 (freehire-search)` (no contact
+- Fetch sends `User-Agent: ai-job-search-dev/ai-job-search/1.0 (freehire-search)` (no contact
   URL: a host literal in `cli/src` makes `/apply` treat that host as this portal's board)
   and `Accept: application/json`, and uses exponential backoff with jitter on 429/5xx (max 6 retries). A connection error (API
   unreachable) fails fast with a clear message — no retry, since it is not