chore(docker-dev): site-b-2 is Cluster:Roles-only, site-a-2 pins a miscased Cluster:Roles entry (archreview 01/S-12, 01/C-9)

T11: site-b-2 drops OTOPCUA_ROLES entirely — Cluster:Roles is its sole role source, the rig's
only node that can exhibit the two-role-authority split (01/S-12). Expected to fail every
deploy on a pre-R3-04 build.

T12: site-a-2 pins Cluster__Roles__0="Driver" (capital D) as the standing 01/C-9 case-mismatch
pin, keeping cluster-SITE-A verbatim. Pre-fix this un-elects the SITE-A Primary.

Combined into one commit (deviation from the plan's two separate T11/T12 commits): the header
comment block documenting all six nodes' role sources interleaves both nodes on adjacent lines,
so a clean split was not practical. Recorded in the plan's Execution notes.

Compose edits only — the rig is NOT brought up as part of this change.

archreview/plans/R3-04-one-role-authority-plan.md.tasks.json

@@ -83,13 +83,13 @@
     {
       "id": "T11",
       "subject": "docker-dev: site-b-2 becomes Cluster:Roles-only so the rig can exhibit the two-authority split (theme 2 rig-fidelity)",
-      "status": "pending",
+      "status": "completed",
       "blockedBy": []
     },
     {
       "id": "T12",
       "subject": "docker-dev: site-a-2 pins a miscased Cluster__Roles__0 = 'Driver' as the standing 01/C-9 pin",
-      "status": "pending",
+      "status": "completed",
       "blockedBy": []
     },
     {