Add IPFS_PRIMARY environment variable for server

When IPFS_PRIMARY=true:
- /api/run-recipe uses run_recipe_cid task
- Recipe registered on IPFS before execution
- Input CIDs fetched from cache manager
- Everything flows through IPFS, no local cache

Usage in docker-compose:
  environment:
    - IPFS_PRIMARY=true

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

server.py

@@ -70,6 +70,10 @@ def compute_run_id(input_hashes: list[str], recipe: str, recipe_hash: str = None
 # IPFS gateway URL for public access to IPFS content
 IPFS_GATEWAY_URL = os.environ.get("IPFS_GATEWAY_URL", "")
 
+# IPFS-primary mode: everything stored on IPFS, no local cache
+# Set to "true" to enable
+IPFS_PRIMARY = os.environ.get("IPFS_PRIMARY", "").lower() in ("true", "1", "yes")
+
 # Cache directory (use /data/cache in Docker, ~/.artdag/cache locally)
 CACHE_DIR = Path(os.environ.get("CACHE_DIR", str(Path.home() / ".artdag" / "cache")))
 CACHE_DIR.mkdir(parents=True, exist_ok=True)
@@ -6196,9 +6200,9 @@ async def run_recipe_endpoint(
     3. Execute: Run steps with parallel execution
 
     Returns immediately with run_id. Poll /api/run/{run_id} for status.
-    """
-    from tasks.orchestrate import run_recipe
 
+    Set IPFS_PRIMARY=true to use IPFS-primary mode (everything on IPFS).
+    """
     # Compute run_id from inputs and recipe
     try:
         recipe_data = yaml.safe_load(request.recipe_yaml)
@@ -6227,12 +6231,43 @@ async def run_recipe_endpoint(
 
     # Submit to Celery
     try:
-        task = run_recipe.delay(
-            recipe_yaml=request.recipe_yaml,
-            input_hashes=request.input_hashes,
-            features=request.features,
-            run_id=run_id,
-        )
+        if IPFS_PRIMARY:
+            # IPFS-primary mode: register recipe and get input CIDs
+            from tasks.orchestrate_cid import run_recipe_cid
+            import ipfs_client
+
+            # Register recipe on IPFS
+            recipe_cid = ipfs_client.add_bytes(request.recipe_yaml.encode('utf-8'))
+            if not recipe_cid:
+                raise HTTPException(status_code=500, detail="Failed to register recipe on IPFS")
+
+            # Get input CIDs from cache manager
+            input_cids = {}
+            for name, content_hash in request.input_hashes.items():
+                cid = cache_manager.get_ipfs_cid(content_hash)
+                if cid:
+                    input_cids[name] = cid
+                else:
+                    raise HTTPException(
+                        status_code=400,
+                        detail=f"Input '{name}' not found on IPFS. Upload first."
+                    )
+
+            task = run_recipe_cid.delay(
+                recipe_cid=recipe_cid,
+                input_cids=input_cids,
+                input_hashes=request.input_hashes,
+                features=request.features,
+            )
+        else:
+            # Standard mode: local cache + IPFS backup
+            from tasks.orchestrate import run_recipe
+            task = run_recipe.delay(
+                recipe_yaml=request.recipe_yaml,
+                input_hashes=request.input_hashes,
+                features=request.features,
+                run_id=run_id,
+            )
 
         # Store run status in Redis
         run_data = {