Add observability: health endpoints, structured logging, metrics, Grafana stack

Health endpoints:
- /api/health (Journal) and /health (Planner) with DB connectivity check
- Docker healthchecks updated to use app health endpoints

Structured logging:
- Pino with JSON output in production, pretty-print in dev
- Request logging middleware in Planner (method, path, status, duration)
- Replaced console.log/error with structured logger in email and auth flows

Prometheus metrics:
- prom-client with default Node.js metrics + custom histograms/gauges
- /metrics endpoints on both apps
- http_request_duration, planner_active_sessions, brouter_request_duration

Monitoring stack:
- Prometheus, Loki, Grafana containers in docker-compose
- Grafana provisioned with datasources, dashboards, and alert rules
- Caddy access logging (JSON to stdout for Loki)
- grafana.trails.cool with basic auth via Caddy

Dashboards and alerting:
- Overview: request rate, error rate, latency p50/p95/p99
- Planner: active sessions, connected clients, BRouter latency
- Infrastructure: memory, CPU, event loop lag
- Alerts: disk >80%, app down 2min, error rate >5%

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/planner/package.json

@@ -25,6 +25,8 @@
     "drizzle-orm": "catalog:",
     "isbot": "^5.1.0",
     "lib0": "^0.2.117",
+    "pino": "^10.3.1",
+    "prom-client": "^15.1.3",
     "react": "catalog:",
     "react-dom": "catalog:",
     "react-router": "catalog:",
@@ -39,6 +41,7 @@
     "@types/react": "catalog:",
     "@types/react-dom": "catalog:",
     "@types/ws": "^8.18.1",
+    "pino-pretty": "^13.1.3",
     "tailwindcss": "catalog:",
     "typescript": "catalog:",
     "vite": "catalog:"