```

chore: remove obsolete files and add Solidity build artifacts to .gitignore

- Add ignore patterns for Solidity build artifacts (typechain-types, artifacts, cache)
- Remove unused exchange mock API server (api/exchange_mock_api.py)
- Remove obsolete client-web README placeholder
- Remove deprecated marketplace-ui HTML implementation
```

docs/reference/components/coordinator_api.md

@@ -0,0 +1,84 @@
+# Coordinator API – Task Breakdown
+
+## Status (2026-01-24)
+
+- **Stage 1 delivery**: ✅ **DEPLOYED** - Coordinator API deployed in production behind https://aitbc.bubuit.net/api/
+  - FastAPI service running in Incus container on port 8000
+  - Health endpoint operational: `/api/v1/health` returns `{"status":"ok","env":"dev"}`
+  - nginx proxy configured at `/api/` (so `/api/v1/*` routes to the container service)
+  - Explorer API available via nginx at `/api/explorer/*` (backend: `/v1/explorer/*`)
+  - Users API available via `/api/v1/users/*` (compat: `/api/users/*` for Exchange)
+- **Stage 2 delivery**: ✅ **DEPLOYED** - All import and syntax errors fixed (2025-12-28)
+  - Fixed SQLModel import issues across the codebase
+  - Resolved missing module dependencies
+  - Database initialization working correctly with all tables created
+- **Recent Bug Fixes (2026-01-24)**:
+  - ✅ Fixed missing `_coerce_float()` helper function in receipt service causing 500 errors
+  - ✅ Receipt generation now works correctly for all job completions
+  - ✅ Deployed fix to production incus container via SSH
+  - ✅ Result submission endpoint returns 200 OK with valid receipts
+- **Testing & tooling**: Pytest suites cover job scheduling, miner flows, and receipt verification; the shared CI script `scripts/ci/run_python_tests.sh` executes these tests in GitHub Actions.
+- **Documentation**: `docs/run.md` and `apps/coordinator-api/README.md` describe configuration for `RECEIPT_SIGNING_KEY_HEX` and `RECEIPT_ATTESTATION_KEY_HEX` plus the receipt history API.
+- **Service APIs**: Implemented specific service endpoints for common GPU workloads (Whisper, Stable Diffusion, LLM inference, FFmpeg, Blender) with typed schemas and validation.
+- **Service Registry**: Created dynamic service registry framework supporting 30+ GPU services across 6 categories (AI/ML, Media Processing, Scientific Computing, Data Analytics, Gaming, Development Tools).
+
+
+## Stage 1 (MVP) - COMPLETED
+
+- **Project Setup**
+  - ✅ Initialize FastAPI app under `apps/coordinator-api/src/app/` with `main.py`, `config.py`, `deps.py`.
+  - ✅ Add `.env.example` covering host/port, database URL, API key lists, rate limit configuration.
+  - ✅ Create `pyproject.toml` listing FastAPI, uvicorn, pydantic, SQL driver, httpx, redis (optional).
+
+- **Models & Persistence**
+  - ✅ Design Pydantic schemas for jobs, miners, constraints, state transitions (`models.py`).
+  - ✅ Implement DB layer (`db.py`) using SQLite (or Postgres) with tables for jobs, miners, sessions, worker sessions.
+  - ✅ Provide migrations or schema creation script.
+
+- **Business Logic**
+  - ✅ Implement `queue.py` and `matching.py` for job scheduling.
+  - ✅ Create state machine utilities (`states.py`) for job transitions.
+  - ✅ Add settlement stubs in `settlement.py` for future token accounting.
+
+- **Routers**
+  - ✅ Build `/v1/jobs` endpoints (submit, get status, get result, cancel) with idempotency support.
+  - ✅ Build `/v1/miners` endpoints (register, heartbeat, poll, result, fail, drain).
+  - ✅ Build `/v1/admin` endpoints (stats, job listing, miner listing) with admin auth.
+  - ✅ Build `/v1/services` endpoints for specific GPU workloads:
+    - `/v1/services/whisper/transcribe` - Audio transcription
+    - `/v1/services/stable-diffusion/generate` - Image generation
+    - `/v1/services/llm/inference` - Text generation
+    - `/v1/services/ffmpeg/transcode` - Video transcoding
+    - `/v1/services/blender/render` - 3D rendering
+  - ✅ Build `/v1/registry` endpoints for dynamic service management:
+    - `/v1/registry/services` - List all available services
+    - `/v1/registry/services/{id}` - Get service definition
+    - `/v1/registry/services/{id}/schema` - Get JSON schema
+    - `/v1/registry/services/{id}/requirements` - Get hardware requirements
+  - Optionally add WebSocket endpoints under `ws/` for streaming updates.
+- **Receipts & Attestations**
+  - ✅ Persist signed receipts (latest + history), expose `/v1/jobs/{job_id}/receipt(s)` endpoints, and attach optional coordinator attestations when `RECEIPT_ATTESTATION_KEY_HEX` is configured.
+
+- **Auth & Rate Limiting**
+  - ✅ Implement dependencies in `deps.py` to validate API keys and optional HMAC signatures.
+  - ✅ Add rate limiting (e.g., `slowapi`) per key.
+
+- **Testing & Examples**
+  - ✅ Create `.http` files or pytest suites for client/miner flows.
+  - ✅ Document curl examples and quickstart instructions in `apps/coordinator-api/README.md`.
+
+## Production Deployment Details
+
+- **Container**: Incus container 'aitbc' at `/opt/coordinator-api/`
+- **Service**: systemd service `coordinator-api.service` enabled and running
+- **Port**: 8000 (internal), proxied via nginx at `/api/` (including `/api/v1/*`)
+- **Dependencies**: Virtual environment with FastAPI, uvicorn, pydantic installed
+- **Access**: https://aitbc.bubuit.net/api/v1/health for health check
+- **Note**: Explorer + Users routes are enabled in production (see `/api/explorer/*` and `/api/v1/users/*`).
+
+## Stage 2+ - IN PROGRESS
+
+- 🔄 Integrate with blockchain receipts for settlement triggers.
+- 🔄 Add Redis-backed queues for scalability.
+- 🔄 Implement metrics and tracing (Prometheus/OpenTelemetry).
+- 🔄 Support multi-region coordinators with pool hub integration.