fix: Make coords_3d optional in schema to support UMAP workflow

The proper architecture is:
1. Nodes are created with coords_3d = NONE
2. User manually triggers /api/calculate-graph
3. UMAP calculates 3D coordinates from embeddings
4. Coordinates are updated in batch

Changed coords_3d TYPE from array<number> to option<array<number>>
to allow NONE values. This fixes production error:
"Found NONE for field coords_3d but expected array<number>"

Schema has been deployed to production.

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

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

app/api/nodes/route.ts

@@ -229,7 +229,7 @@ export async function POST(request: NextRequest) {
       atp_uri: atp_uri,
       title: title,
       body: body, // Store the raw text body
-      coords_3d: [0, 0, 0], // Required by schema - origin coordinates for new nodes
+      // coords_3d will be calculated when user runs /api/calculate-graph
     };
 
     // Only include embedding if it was successfully generated

db/schema.surql

@@ -62,8 +62,9 @@ DEFINE FIELD body ON TABLE node TYPE string;
 DEFINE FIELD embedding ON TABLE node TYPE array<number>;
 
 -- The 3D coordinates calculated by UMAP.
-DEFINE FIELD coords_3d ON TABLE node TYPE array<number>
-    -- Must be a 3-point array [x, y, z] or empty.
+-- Nodes start with NONE and get coordinates when user runs calculate-graph.
+DEFINE FIELD coords_3d ON TABLE node TYPE option<array<number>>
+    -- Must be NONE or a 3-point array [x, y, z].
     ASSERT $value = NONE OR array::len($value) = 3;
 
 -- Define the vector search index.