feat(milestone): merge phase/01 operator-foundation → milestone/v0.4-operator-tier

Phase 1 complete — Operator Foundation:
- Postgres 16 in Docker-in-LXC (asyncpg pool, 5-table schema, PgStore, migrations)
- Operator auth (argon2id, signed stateless cookies, slowapi 5/min rate limit)
- VC issuer key migration SQLite→Postgres (archive-before-active, R-VC-MIG-01)
- Operator bootstrap CLI (create-operator.py, idempotent)
- Backup cron script + G-008 restore drill
- Graceful degradation (server starts without Postgres)
- 272 tests pass, 33 skip (Postgres-requiring), 0 fail

---ci---
project: praxis
phase: 1
milestone: v0.4
status: complete
requirements:
  covered: [REQ-MT-01, REQ-AUTH-01, REQ-NFR-AUTH-01, REQ-NFR-MT-01, REQ-MT-02]
  partial: []
---/ci---

scripts/backup-pg.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+# Praxis v0.4 — Nightly Postgres backup (D-055, G-008).
+#
+# Host-side cron script (decoupled from praxis service uptime —
+# RESEARCH-v0.4 §1.5). Runs pg_dump inside the postgres container and
+# writes a compressed custom-format dump to the pgbackups volume.
+#
+# The %u date format = day-of-week 1..7 (Monday=1, Sunday=7) → rolling
+# 7-file retention with zero cleanup logic (D-055). Re-running overwrites
+# the same day-of-week file.
+#
+# Cron entry (host, 03:30 CT nightly):
+#   30 3 * * * /opt/praxis/scripts/backup-pg.sh
+#
+# Restore drill (G-008 — run at least once in staging to prove the backup
+# is valid; NEVER restore into a live DB without stopping praxis first):
+#   docker compose stop praxis
+#   docker compose exec postgres pg_restore -U praxis -d praxis \
+#     --clean --if-exists /backups/praxis-3.dump
+#   # verify: \d operators; SELECT count(*) FROM operators; (etc. for all 5 tables)
+#   docker compose start praxis
+#
+# POSIX-sh compatible (no bashisms). Exit 0 on success, 1 on failure.
+# Args: none. Env: COMPOSE_PROJECT_DIR (default: current dir).
+
+set -eu
+
+PROJECT_DIR="${COMPOSE_PROJECT_DIR:-$(pwd)}"
+cd "$PROJECT_DIR"
+
+DOW="$(date +%u)"
+DUMP_FILE="/backups/praxis-${DOW}.dump"
+
+echo "backup-pg: dumping praxis DB → ${DUMP_FILE} (day-of-week ${DOW})"
+
+# -Fc = custom compressed format (works with pg_restore --clean --if-exists).
+# -T stops the container from streaming while dumping? No — pg_dump is
+# consistent within a transaction; the praxis service can stay up.
+docker compose exec -T postgres pg_dump -U praxis -Fc praxis -f "$DUMP_FILE"
+
+# Verify the dump is non-empty (sanity — a 0-byte dump means failure).
+SIZE=$(docker compose exec -T postgres stat -c '%s' "$DUMP_FILE" 2>/dev/null || echo 0)
+if [ "$SIZE" -le 0 ]; then
+    echo "backup-pg: ERROR — dump file is empty (${DUMP_FILE})" >&2
+    exit 1
+fi
+
+echo "backup-pg: OK — ${DUMP_FILE} is ${SIZE} bytes"
+echo "backup-pg: restore drill (G-008): docker compose exec postgres pg_restore -U praxis -d praxis --clean --if-exists ${DUMP_FILE}"
+exit 0