ggml webgpu: ops support for qwen3.5 (SET, TRI_SOLVE, SSM_CONV, GATED_DELTA_NET) + GET_ROWS optimization (#20687)
* Implement l2_norm, set, tri
* Add DIAG/SOLVE_TRI
* Add SSM_CONV
* Better get_rows and gated_delta_net to support qwen3.5
* Clean up, update ops.md
* Fix binding_index type for wasm
* Fix read write annotations
* cleanups