// Workbook-local CUDA sketch for FlashAttention forward.
//
// Map this against the Triton sketch:
// - Triton program_id for query tile -> CUDA block ownership
// - Triton block pointer loads        -> CUDA cooperative global-to-shared loads
// - Triton masks                      -> explicit edge and causal checks
// - Triton implicit block math        -> thread/block index arithmetic

// TODO(student):
// 1. Assign a block to one batch/head/query tile.
// 2. Load a Q tile and loop over K/V tiles.
// 3. Compute score tiles and causal masking.
// 4. Update online softmax state.
// 5. Accumulate the output tile.