Add Agent-Generated to ci-mx's always-on label set

The repo already has an 'Agent-Generated' label that other automation
uses. Adding it to ci-mx's fix-PR creation so reviewers can filter all
agent-authored PRs uniformly.

The three existing PoC PRs (#4442, #4443, #4444) were also relabeled.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jpayne3506

.github/agents/ci-mx.md

@@ -557,14 +557,14 @@ esac
 
 ### Label generation
 
-Always-on: `ci`. Govulncheck commits add `dependencies`. File-touched
-heuristic adds repo-existing area labels (`cni`, `cns`, `cilium`,
-etc.) when matching paths appear in the commit's diff. The set is
-filtered against `gh label list` to skip any label that doesn't exist
-in the repo (no auto-creation).
+Always-on: `ci`, `Agent-Generated`. Govulncheck commits add
+`dependencies`. File-touched heuristic adds repo-existing area labels
+(`cni`, `cns`, `cilium`, etc.) when matching paths appear in the
+commit's diff. The set is filtered against `gh label list` to skip any
+label that doesn't exist in the repo (no auto-creation).
 
 ```bash
-labels=("ci")
+labels=("ci" "Agent-Generated")
 [ "${RAN_GOVULNCHECK:-false}" = "true" ] && labels+=("dependencies")
 
 # Derive area labels from the commit's diff (HEAD~..HEAD covers both