First pass at nodes

AGENTS.md

@@ -94,6 +94,12 @@ void prNodeDestroy(PrNode *n, PrAllocator *alloc);
 Use wapp allocators (`WpAllocator`, arena-based). Stack-allocate where
 possible; pass allocators explicitly.
 
+**Never use libc for memory or file I/O.** wapp always takes precedence:
+- `wpMemAllocatorAlloc` / `wpMemAllocatorFree` instead of `malloc` / `free`
+- `wpFileOpen` / `wpFileRead` / `wpFileClose` instead of `fopen` / `fread` / `fclose`
+
+For one-shot loads (e.g. SPIR-V at init), use `&_G_RHI_CONTEXT.allocator`.
+
 ```c
 PrGraph *prGraphCreate(PrAllocator *alloc);
 void     prGraphDestroy(PrGraph *g, PrAllocator *alloc);