feat(polygon): Add Polygon PoS Full Node Blueprint using Erigon

[snese]

Add Polygon PoS Full Node Blueprint

Adds a Polygon PoS blueprint under lib/polygon/ using Erigon as a single-container all-in-one client, with both single-node and highly-available deployment options.

Architecture

Uses 0xpolygon/erigon:v3.4.0 (Polygon's fork of Erigon) with --chain=bor-mainnet and --bor.heimdall=https://heimdall-api.polygon.technology. Single container per node, no separate Heimdall node needed.

Why Erigon over Heimdall+Bor: The traditional dual-container approach (Heimdall + Bor) is currently unreliable due to the ongoing Heimdall v1→v2 migration. Erigon provides a simpler, single-container alternative that connects to Polygon's official Heimdall API endpoint. See heimdall-v2#568 for the Docker image issues we found.

What's included

• CDK Stacks:
  • polygon-common — IAM role, exports
  • polygon-single-node — Single EC2 instance with CloudWatch dashboard (reuses SingleNodeConstruct)
  • polygon-ha-nodes — ALB + ASG multi-AZ HA setup (reuses HANodesConstruct)
• Config: .env based, with mainnet and amoy sample configs
• User-data: Docker CE from official repo (with compose plugin), EBS volume detection, Erigon startup, CloudWatch metrics cron (IMDSv2)
• Security: P2P (30303) and torrent sync (42069) public; RPC (8545) VPC-internal only; --http.vhosts=localhost,127.0.0.1; data dir owned by UID 1000 with mode 750
• Tests: 4 Jest tests across 2 suites (common stack, cdk-nag, single-node stack, HA nodes stack) — all passing
• README: Full deployment guide for both single and HA, Well-Architected checklist
• Website: Docusaurus page at website/docs/Blueprints/Polygon.md
• CI: Removed polygon from test exclusion list in run-all-cdk-tests.sh

Hardware specs

Network	Instance	Storage	IOPS	Throughput	Est. cost
Mainnet	m7g.4xlarge (Graviton3)	8 TB gp3	16,000	1,000 MB/s	~$1,100/mo per node
Amoy	m7g.xlarge (Graviton3)	1 TB gp3	5,000	250 MB/s	~$250/mo per node

Storage specs per Polygon official docs.

Deployment verification

• Single node: CDK CREATE_COMPLETE (8/8 resources) in us-east-1, Erigon syncing Amoy via OtterSync, 21 peers, RPC responding, Graviton ARM
• HA nodes: CDK CREATE_COMPLETE (17/17 resources), ALB + ASG with 2 nodes, health checks passing

Key design decisions

1. Erigon single-container — Avoids Heimdall v1→v2 migration issues entirely. Connects to Polygon's official Heimdall API endpoint.
2. OtterSync — Erigon's built-in torrent-based snapshot sync. No manual snapshot download needed.
3. No CreationPolicy/cfn-signal for single-node — Removed to avoid circular dependency with VolumeAttachment. HA stack uses LaunchTemplate (no circular dependency). Node health monitored via CloudWatch.
4. Docker CE from official repo — Uses docker-compose-plugin instead of standalone binary, no checksum management needed.

Closes #7
Refs #233

[frbrkoala]

All good! Thanks a lot for your contribution!