infra(cpb): rewrite DB setup script and add schema for Connecting People Bot

Replace the old setup script that required postgres admin access and CREATEROLE
with a version that uses temporal user (CREATEDB) and grants to existing n8n user.
Add complete 6-table schema (cycles, opt_in_responses, pairings, pair_history,
interactions, admin_reports) with idempotent IF NOT EXISTS, triggers, and indexes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: SashkoMarchuk

scripts/cpb-setup-db.sh

@@ -0,0 +1,108 @@
+#!/bin/bash
+set -eo pipefail
+
+# =============================================================================
+# CPB Production Database Setup
+# =============================================================================
+# Creates the cpb_bot database on an external PostgreSQL (RDS) server using the
+# temporal user (which has CREATEDB privilege). Grants access to the n8n user
+# so the CPB application (running inside n8n) can manage its tables.
+#
+# Ownership model:
+#   - temporal creates and owns the database (only user with CREATEDB)
+#   - n8n gets ALL PRIVILEGES on the database to create/manage tables
+#   - Later, when DevOps provides the master password, ownership can be
+#     migrated to a dedicated cpb_app user
+#
+# PostgreSQL version notes:
+#   - PG14: public schema grants CREATE to PUBLIC by default — n8n can create
+#     tables without explicit schema grants
+#   - PG15+: CREATE on public schema is revoked by default — the script
+#     attempts to grant schema privileges and warns if it cannot (the DB owner
+#     can do this on PG15+ since public schema is owned by pg_database_owner)
+#
+# Usage:
+#   CPB_POSTGRES_HOST="<host>" POSTGRES_PASSWORD_TEMPORAL="<pw>" \
+#     POSTGRES_USER_N8N="n8n" ./scripts/cpb-setup-db.sh
+#
+# Required env vars:
+#   CPB_POSTGRES_HOST          — PostgreSQL server hostname or IP
+#   POSTGRES_PASSWORD_TEMPORAL — Password for the temporal user
+#
+# Optional env vars:
+#   CPB_POSTGRES_PORT          — PostgreSQL port (default: 5432)
+#   POSTGRES_USER_TEMPORAL     — Temporal user name (default: temporal)
+#   POSTGRES_USER_N8N          — n8n user to grant access to (default: n8n)
+#   POSTGRES_DB_CPB            — Database name (default: cpb_bot)
+# =============================================================================
+
+PGHOST="${CPB_POSTGRES_HOST:?CPB_POSTGRES_HOST is required}"
+PGPORT="${CPB_POSTGRES_PORT:-5432}"
+TEMPORAL_USER="${POSTGRES_USER_TEMPORAL:-temporal}"
+N8N_USER="${POSTGRES_USER_N8N:-n8n}"
+CPB_DB="${POSTGRES_DB_CPB:-cpb_bot}"
+
+TEMPORAL_PASS="${POSTGRES_PASSWORD_TEMPORAL:?POSTGRES_PASSWORD_TEMPORAL is required}"
+
+# Validate PostgreSQL identifiers (prevent SQL injection via crafted names)
+validate_pg_identifier() {
+    local value="$1" name="$2"
+    if [[ -z "$value" ]]; then
+        echo "ERROR: ${name} cannot be empty" >&2; exit 1
+    fi
+    if [[ ${#value} -gt 63 ]]; then
+        echo "ERROR: ${name} exceeds PostgreSQL's 63-char identifier limit" >&2; exit 1
+    fi
+    if [[ ! "$value" =~ ^[a-zA-Z_][a-zA-Z0-9_]*$ ]]; then
+        echo "ERROR: ${name} contains invalid characters (must match ^[a-zA-Z_][a-zA-Z0-9_]*$)" >&2; exit 1
+    fi
+    return 0
+}
+validate_pg_identifier "$TEMPORAL_USER" "POSTGRES_USER_TEMPORAL"
+validate_pg_identifier "$N8N_USER" "POSTGRES_USER_N8N"
+validate_pg_identifier "$CPB_DB" "POSTGRES_DB_CPB"
+
+echo "Setting up CPB database on ${PGHOST}:${PGPORT}..."
+echo "  Database:  ${CPB_DB}"
+echo "  Owner:     ${TEMPORAL_USER} (interim — migrate to dedicated user later)"
+echo "  Grantee:   ${N8N_USER}"
+
+# --- Step 1: Create database and grant database-level privileges -----------
+# Connect to the 'postgres' maintenance database to run DDL.
+# CREATE DATABASE cannot run inside a transaction, so we use \gexec.
+PGPASSWORD="${TEMPORAL_PASS}" psql -v ON_ERROR_STOP=1 \
+    -h "$PGHOST" -p "$PGPORT" -U "$TEMPORAL_USER" -d postgres <<-EOSQL
+-- Create database if it doesn't exist (temporal becomes owner)
+SELECT 'CREATE DATABASE "${CPB_DB}"'
+WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '${CPB_DB}')\gexec
+
+-- Grant all database-level privileges to n8n (idempotent)
+GRANT ALL PRIVILEGES ON DATABASE "${CPB_DB}" TO "${N8N_USER}";
+EOSQL
+
+# --- Step 2: Grant schema-level privileges ---------------------------------
+# On PG14, this is unnecessary (PUBLIC has CREATE on public schema by default)
+# but we attempt it for forward-compatibility with PG15+ where it IS required.
+# temporal cannot grant on public schema in PG14 (owned by postgres), so we
+# handle the error gracefully.
+SCHEMA_GRANT_ERR=$(PGPASSWORD="${TEMPORAL_PASS}" psql -v ON_ERROR_STOP=1 \
+    -h "$PGHOST" -p "$PGPORT" -U "$TEMPORAL_USER" -d "$CPB_DB" \
+    -c "GRANT ALL ON SCHEMA public TO \"${N8N_USER}\";" 2>&1) && \
+    echo "  Schema grant on public: OK" || {
+    if echo "$SCHEMA_GRANT_ERR" | grep -qi "permission denied\|must be owner"; then
+        echo "  Schema grant on public: skipped (not needed on PG14 — PUBLIC has CREATE by default)"
+        echo "  NOTE: After upgrading to PG15+, re-run this script or grant manually:"
+        echo "    GRANT ALL ON SCHEMA public TO \"${N8N_USER}\";"
+    else
+        echo "ERROR: Schema grant failed unexpectedly:" >&2
+        echo "  $SCHEMA_GRANT_ERR" >&2
+        exit 1
+    fi
+}
+
+echo ""
+echo "CPB database setup complete."
+echo "  Database: ${CPB_DB}"
+echo "  Owner:    ${TEMPORAL_USER}"
+echo "  Access:   ${N8N_USER} (all privileges)"
+echo "  Host:     ${PGHOST}:${PGPORT}"