fix(freehire-search): drop the github.com URL from the User-Agent (#689)

* fix(freehire-search): drop the github.com URL from the User-Agent

#633 put a contact URL in freehire-search's User-Agent. /apply learns which
hosts an installed portal serves from the host literals in its cli/src, so
github.com became a freehire-search board host: any github.com link (a repo
README or gist presented as a job posting) classified as an installed
portal instead of an unverified source host.

Keep the owner/project/version identifier freehire's API docs ask for and
drop the optional contact URL. Pin github.com and gist.github.com as
unverified in the host-check test.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QhZWmcevg3UX9udYi1CsHC

* changelog: place the #689 entry under [Unreleased]

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Mads Lorentzen <madslorentzen_17@hotmail.com>

tests/test_apply_host_check.py

@@ -292,6 +292,11 @@ class InstalledPortalsAreVerifiedTests(unittest.TestCase):
             "https://myworkdayjobs.com.phishing.net/login",
             "https://lever.co.attacker.org/apply",
             "https://unknown-board.example.com/posting/123",
+            # Anyone can publish a "job posting" in a GitHub repo or gist. A
+            # contact URL in a portal CLI's User-Agent string once made
+            # github.com an installed-portal host (#633), so pin it here.
+            "https://github.com/acme-careers/jobs/blob/main/README.md",
+            "https://gist.github.com/someone/0123456789abcdef",
         ]
         for url in suspicious:
             tier, host = classify_posting_host(url)