docs(#771): remediate Ultron role and migration findings

docs/scratchpads/771-kbn101-db-role-split.md

@@ -117,3 +117,12 @@ Independent Codex review found two blockers and security review found two medium
 - **Validation:** Prettier check, strict native-kanban contract TypeScript, changed-document local-link resolution, `git diff --check`, and an automated manifest-overlap/owner/current-source-path check passed. Targeted documentation/security review verified role ownership/default privileges/search path/preflight/legacy/shadow/rollback consistency, disjoint manifests/DAG/activation, scanner mechanics, exact bin/entrypoint, and no `.mosaic` staging intent. No source-code TDD applies because this is documentation-only remediation.
 - **Next:** stage documentation only, commit, queue-guard, push, verify exact remote SHA, then wait for fresh exact-head review.
 - **Delivery evidence:** committed `8cbad2bcd9bc7507052f74f35670ef7c8e39e44e` as `docs(#771): close role split rc.9 residuals`; `ci-queue-wait.sh --purpose push -B main` returned `state=unknown` without error; push-hook `pnpm typecheck`, `pnpm lint`, and `pnpm format:check` all passed; push succeeded and `origin/docs/771-kbn101-db-role-split` resolved to that exact SHA. Pre-existing `.mosaic/orchestrator/{mission.json,session.lock}` remains modified but intentionally unstaged/excluded. The only next action is a fresh independent exact-head re-review.
+
+## 2026-07-15 — rc.10 Ultron NO-GO remediation intake
+
+- **Objective / scope:** Close only HIGH-1 and HIGH-2 in `/home/hermes/agent-work/reviews/771-kbn101-ultron-11f09a1.md` against exact head `11f09a15e43e72afda6a0374668996b4bda9e536`. Documentation only: preserve approved content; no source/config/Compose/CI/deploy/secret/migration edits and no `.mosaic` staging.
+- **Plan:** (1) replace the impossible `NOLOGIN NOSUPERUSER` extension owner with the exact non-login, zero-member `NOLOGIN SUPERUSER` external-control exception and document the non-delegable superuser residual; (2) require the audited external superuser session to `SET ROLE`/`RESET ROLE` for fresh, approved-owner, and shadow extension work, then prove catalog ownership and all service-role denial; (3) assign the active migrate-tier guide exclusively to KBN-101-07, add its active secure route to the -06 inventory/matrix/scanner schema, and freeze `--target-url-file /run/secrets/mosaic_migrate_target_url` plus pre-migrated target/dedicated non-DDL importer requirements; (4) synchronize PRD/shared/tasks/index/sitemap/guide and rc.10 status; (5) validate formatting, links, contracts, source paths, finite operator inventory, diff, review, commit, queue guard, push, and exact remote SHA.
+- **Target-image evidence before edits:** local `pgvector/pgvector:pg17` control file reports `default_version = '0.8.2'`, `relocatable = true`, and no `trusted`/`superuser` override (untrusted PostgreSQL extension). An isolated PostgreSQL 17 container proved a `NOLOGIN SUPERUSER` `mosaic_extension_owner` can create `mosaic_extensions` and `vector` under external-superuser `SET ROLE`, returns to the external session after `RESET ROLE`, has `rolcanlogin=false`, `rolsuper=true`, zero role members, exact extension/schema and owner-bearing-member ownership, and denies `SET ROLE`, `ALTER EXTENSION`, `DROP EXTENSION`, and schema ownership changes to runtime, migrator, schema owner, and data importer. Ownerless PostgreSQL catalog member classes (`pg_am`, `pg_cast`) were intentionally not misrepresented as ownable members.
+- **TDD decision:** skipped as not applicable: this is a documentation-only contract remediation. Future KBN-101-00/-02/-06 tests are specified as the situational evidence; no source/test artifact is permitted in this task.
+- **Final scope correction:** Per control-plane direction, remediation remains bounded to the two Ultron findings. The active guide is explicitly a non-operative KBN-101 contract until its owned implementation/activation lands; no additional design, source, CI, deployment, secret, or test artifact was added.
+- **Validation evidence:** target-image/container role proof PASS (pgvector `0.8.2`, `relocatable=true`, trusted absent/untrusted; external-superuser `SET ROLE`/`RESET ROLE`; exact extension/schema/owner-bearing-member ownership; zero membership and service-role denials). Changed-doc Prettier, strict native-kanban contract TypeScript, local-link resolver (8 docs), finite operator-doc inventory (one active KBN-101-07 route with no credential argv in executable blocks), source-path check (6 current paths), and `git diff --check` PASS. Pre-existing `.mosaic/orchestrator/{mission.json,session.lock}` remains intentionally excluded.