feat(2): Q4.7 plausible — ops + lifecycle overlays (postgres ci_marker; pg_dump backup hook)

plausible (analytics; app + postgres db + clickhouse events_db). recipe_meta stub (DISABLE_AUTH/
REGISTRATION + SECRET_KEY_BASE) + health test pre-existing. Added ops.py (postgres ci_marker via db
service, container-env psql) + test_install/upgrade/backup/restore overlays. plausible's postgres has a
real pg_dump backup/restore hook (so P4 marker survives, unlike immich). §4.3 event-tracking test next
(after live-API discovery). Tags annotated.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/plausible/test_backup.py

@@ -0,0 +1,17 @@
+"""plausible — BACKUP overlay (Phase 1e HC3): data-integrity, assertion-only. Reads the postgres
+ci_marker via psql in the `db` service (plausible's metadata DB; pg_dump backup hook)."""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "..", "runner"))
+from harness import lifecycle  # noqa: E402
+
+
+def _psql(domain, sql):
+    cmd = f'PGPASSWORD="$POSTGRES_PASSWORD" psql -U "$POSTGRES_USER" -d "$POSTGRES_DB" -tAc "{sql}"'
+    return lifecycle.exec_in_app(domain, ["sh", "-c", cmd], service="db").strip()
+
+
+def test_backup_captures_state(live_app):
+    assert _psql(live_app, "SELECT v FROM ci_marker;") == "original", "seeded postgres state not present at backup time"