feat: AI security controls + PostgreSQL hardening (Week 1 Quick Wins)

AI Security (EGAI 4.3.1.3, 4.3.1.4, 4.1.3.1, IAAI 3.6.26):
- AI Disclaimer banner in ChatPanel: "AI responses may be inaccurate"
- "AI Generated" violet badge on: chat messages, AI summaries,
  project narratives, AI-generated cover images
- HITL: system prompt now requires explicit user confirmation
  before any data mutation (strongly worded instruction)
- Mutation tool audit logging: all 31 write tools logged with
  tool name, params, userId, userRole via Pino

PostgreSQL Hardening (PG Standard V1.6):
- Audit logging: log_connections, log_disconnections, log_statement=ddl,
  log_min_duration_statement=1000 in docker-compose
- SUPERUSER removal script: scripts/harden-postgres.sh
  (NOSUPERUSER + minimal GRANT for app user)
- Health check: pg_isready -U capakraken -d capakraken
- Documentation: security-architecture.md Section 12 updated

Controls closed: EGAI 4.1.3.1, 4.3.1.3, 4.3.1.4, PG 3.3, 3.5

Co-Authored-By: claude-flow <ruv@ruv.net>

docker-compose.prod.yml

@@ -8,10 +8,17 @@ services:
       POSTGRES_DB: capakraken
       POSTGRES_USER: capakraken
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-changeme}
+    command: >
+      postgres
+      -c log_connections=on
+      -c log_disconnections=on
+      -c log_statement=ddl
+      -c log_line_prefix='%t [%p] %u@%d '
+      -c log_min_duration_statement=1000
     volumes:
       - capakraken_prod_pgdata:/var/lib/postgresql/data
     healthcheck:
-      test: ["CMD-SHELL", "pg_isready -U capakraken"]
+      test: ["CMD-SHELL", "pg_isready -U capakraken -d capakraken"]
       interval: 10s
       timeout: 5s
       retries: 5