[Verifieddanny]

closes Issue #5 — Redis Pub/Sub Integration

• internal/ws/pubsub.go: Redis client, Subscribe/Publish/PublishLeaderboardUpdate
• internal/ws/hub.go: leaderboard channel key, RegisterLeaderboard, BroadcastLeaderboard
• All state changes (proposal, winner, settlement) now publish to Redis pub/sub alongside local WebSocket broadcast — enables horizontal scaling

closes Issue #6 — Scoring Engine

• internal/scoring/engine.go: deterministic 4-criterion weighted scorer Weights: execution efficiency (35%), win rate (25%), slippage (25%), reputation (15%)
• New agents seeded with neutral 0.5 on slippage + reputation — can compete from day one
• Tie-break: earlier proposal wins — fully deterministic, no randomness
• handlers/executions.go SelectWinner(): replaced stub with real engine Fetches agent_reputations, runs engine, persists individual scores back to proposals table

closes Issue #7 — Execution Validation Service

• internal/validation/service.go: 6-constraint validation — token pair, slippage, deadline, approved venue, intent ownership, agent ID presence
• All checks run on every call — caller always gets the full failure list
• handlers/executions.go ValidateExecution(): replaced stub with real service Failed proposals get score zeroed (penalises agent in future scoring) HTTP 422 Unprocessable Entity on failure (semantically correct)
• handlers/executions.go SettleExecution(): validation added as hard gate Cannot settle without passing — runs independently of /validate endpoint

closes Issue #8 — Circle Integration

• internal/circle/client.go: isolated Circle API client CreateWallet (deterministic idempotency via SHA1 UUID from wallet address) GetWallet / GetBalance (USDC balance reads) SendUSDC (micropayment settlement — agent execution fee) SimulateCCTPTransfer (cross-chain routing demo) Sandbox/production toggled from ENV — never hits prod from dev
• internal/handlers/circle.go: 4 new endpoints POST /api/v1/wallets, GET /api/v1/wallets/{id}/balance POST /api/v1/wallets/transfer, POST /api/v1/wallets/cctp
• handlers/executions.go SettleExecution(): Circle.SendUSDC() called after settlement Idempotency key tied to execution ID — retries never double-pay Agent total_intents_won + consecutive_successes incremented atomically (gorm.Expr)

CI/CD fixes

• golangci-lint-action upgraded v3 → v6
• Linter now installed via go install (compiled with Go 1.26, no version mismatch)
• actions/upload-artifact, actions/cache, codecov/codecov-action all bumped to v4
• errcheck fix: json.Encode return value checked in respondJSON

README

• Full rewrite reflecting complete backend scope
• Added Circle badge, scoring weights table, validation constraints table
• Full API reference table (13 endpoints)
• WebSocket events table with message shape example
• Updated project structure with all new packages
• All 7 issues marked ✅ Done

Verified end-to-end:
Intent → proposal → scoring engine (0.841) → validation passed → settlement confirmed → leaderboard updated ✅