scripts: publish unified Agent artifacts and restore CI coverage [CI]

Remove Probe build jobs and release paths. Transfer Gitea publishing credentials to both Agent architecture jobs, publish each platform archive once, and run slow tests after development images are published.

ci/fetch-quic-test-runtime.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Prepare the native MsQuic runtime for in-process Agent/Probe tests.
+# Prepare the native MsQuic runtime for in-process Agent tests.
 # Debian packages are extracted locally (no root install); downloads live in
 # the persistent backend test cache so fast and slow workflows reuse them.
 set -euo pipefail