Gossip protocol: relay-to-relay direct sync

[theonlyhennygod]

v0.0.9 — Gossip Protocol

Problem

All sync goes through the central server (hub-and-spoke). If the central server goes down, nodes cannot discover or sync from each other.

Acceptance Criteria

• Nodes exchange peer lists during sync (GET /rpc/peers already exists)
• SyncClient can connect directly to other self-hosted nodes
• Event deduplication across multiple relay sources (by event ID)
• Configurable peer relay list in sync client
• Node health scoring (track sync reliability, uptime)
• Fallback: if central relay is unreachable, sync with known peers
• E2E test: 3 nodes, middle node goes down, other 2 sync directly

Files to create/modify

• apps/api/src/lib/sync/client.ts (add multi-relay support)
• apps/api/src/lib/sync/gossip.ts (NEW — peer discovery + direct sync)
• apps/api/src/trpc/routers/sync.ts (return peer URLs in sync response)
• apps/api/scripts/test-gossip.ts (NEW)

Test

bun run test:gossip

Version bump

All package.json files: 0.0.8 to 0.0.9