P14-03: Prove new-PID pairs inside the roster; declare UIDs and policy pins

- tests/s2/test_new_pid_pairs.gd runs each writer/reader save-restart pair as
  two real child processes and keeps their complete output in the private
  profile, since the script-level roster runs suites without arguments.
- Commit the Godot UIDs of scripts added this session (and the pre-existing
  peeping-room scripts that lacked tracked UIDs) plus the legacy fixture's
  thumbnail import, so a private import generates nothing undeclared.
- Repin suite-policy source SHAs for test_main_dashboard (A06 HUD, palette 25)
  and test_runtime_transport (sustained outage helper); flags unchanged.
- Register the pair suite's completion marker.

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

tools/regression/suite-policy.json

@@ -191,7 +191,7 @@
       "new_audio_QA": false
     },
     "tests/ui/test_main_dashboard.gd": {
-      "source_sha256": "fa9ee0c4b9aee00a2be6d05a9dab7c0c3e8b0beb2b944257de1dc308bfc3cc20",
+      "source_sha256": "305227c1077a92ef3ee522b561a68b0685767740b46b51ff789c800931647ef1",
       "ordinary_cleanup_prepared": false,
       "ordinary_control_labels": [],
       "old_bounded_teardown": true,
@@ -379,7 +379,7 @@
       "source_only_ownership_review": true
     },
     "tests/transport/test_runtime_transport.gd": {
-      "source_sha256": "ec6f8fa8e8f2a76a6f6214b4ee84861aba1bb13845a342c5126905b01f428a15",
+      "source_sha256": "78a5563ff2421ae65a0988cf0d26669f54bcc0f44250b00e5334cadf1228da94",
       "ordinary_cleanup_prepared": true,
       "ordinary_control_labels": [
         "single"