feat: L1 server with persistent run storage

- FastAPI server on port 8100
- POST /runs to start rendering jobs
- GET /runs/{id} to check status
- Cache and run persistence in Redis
- Auto-generated API docs at /docs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -1,12 +1,12 @@
 # Art Celery
 
-Distributed rendering for the Art DAG system using Celery.
+L1 rendering server for the Art DAG system. Manages distributed rendering jobs via Celery workers.
 
 ## Dependencies
 
 - **artdag** (GitHub): Core DAG execution engine
 - **artdag-effects** (rose-ash): Effect implementations
-- **Redis**: Message broker and result backend
+- **Redis**: Message broker, result backend, and run persistence
 
 ## Setup
 
@@ -19,9 +19,48 @@ pip install -r requirements.txt
 
 # Start a worker
 celery -A celery_app worker --loglevel=info
+
+# Start the L1 server
+python server.py
 ```
 
-## Usage
+## L1 Server API
+
+Interactive docs: http://localhost:8100/docs
+
+### Endpoints
+
+| Method | Path | Description |
+|--------|------|-------------|
+| GET | `/` | Server info |
+| POST | `/runs` | Start a rendering run |
+| GET | `/runs` | List all runs |
+| GET | `/runs/{run_id}` | Get run status |
+| GET | `/cache` | List cached content hashes |
+| GET | `/cache/{hash}` | Download cached content |
+| POST | `/cache/import?path=` | Import local file to cache |
+| GET | `/assets` | List known assets |
+
+### Start a run
+
+```bash
+curl -X POST http://localhost:8100/runs \
+  -H "Content-Type: application/json" \
+  -d '{"recipe": "dog", "inputs": ["33268b6e..."], "output_name": "my-output"}'
+```
+
+### Check run status
+
+```bash
+curl http://localhost:8100/runs/{run_id}
+```
+
+## Storage
+
+- **Cache**: `~/.artdag/cache/` (content-addressed files)
+- **Runs**: Redis db 5, keys `artdag:run:*` (persists across restarts)
+
+## CLI Usage
 
 ```bash
 # Render cat through dog effect
@@ -37,19 +76,23 @@ python render.py dog cat
 ## Architecture
 
 ```
-render.py (CLI)
+server.py (L1 Server - FastAPI)
     │
-    ▼
-celery_app.py (Celery broker)
+    ├── POST /runs → Submit job
+    │       │
+    │       ▼
+    │   celery_app.py (Celery broker)
+    │       │
+    │       ▼
+    │   tasks.py (render_effect task)
+    │       │
+    │       ├── artdag (GitHub) - DAG execution
+    │       └── artdag-effects (rose-ash) - Effects
+    │               │
+    │               ▼
+    │           Output + Provenance
     │
-    ▼
-tasks.py (render_effect task)
-    │
-    ├── artdag (GitHub) - DAG execution
-    └── artdag-effects (rose-ash) - Effect implementations
-           │
-           ▼
-       Provenance JSON + Output file
+    └── GET /cache/{hash} → Retrieve output
 ```
 
 ## Provenance