Add missing Phase-6 evidence items to fleet progression spec

- Add scripts/fleet_phase6_network.py as Phase-6 evaluator
- Add docs/FLEET_PHASE_6_NETWORK.md as committed network report
- These were landed in PR #838 but omitted from repo_evidence list

Closes #553

configs/fleet_progression.json

@@ -166,6 +166,14 @@
           "path": "scripts/autonomous_issue_creator.py",
           "description": "Autonomous incident creation"
         },
+        {
+          "path": "scripts/fleet_phase6_network.py",
+          "description": "Phase-6 network state evaluator and report generator"
+        },
+        {
+          "path": "docs/FLEET_PHASE_6_NETWORK.md",
+          "description": "Committed Phase-6 network status report"
+        },
         {
           "path": "scripts/setup-syncthing.sh",
           "description": "Global mesh scaffolding"