Harden Render deployment guide and Blueprint path

[NickCrew]

Description

Make Render a supported managed-hosting path rather than an incidental render.yaml. The guide should explain the existing Blueprint, identify required manual environment values, and document how operators verify Fleet API/UI behavior after deploy.

Keep WAF deployment as a separate container/self-hosted or Fly/Kubernetes concern unless a Render-specific WAF path is validated.

Acceptance Criteria

• Migrate synapse-waf to Rust 2024 edition #1 Render guide maps the existing Blueprint services to Fleet UI, Fleet API, Postgres, Redis/Key Value, env vars, health checks, and predeploy migrations
• Cache parsed EvalContext data across body-phase and deferred WAF passes #2 Guide documents required secret values, CORS/WebSocket URLs, and production ClickHouse posture
• Instantiate and integrate HeaderProfiler for per-endpoint header anomaly detection #3 Guide includes verification steps for health, REST, WebSocket dashboard, and sensor telemetry connectivity

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Migrated from backlog TASK-103.8 (synapse).