fix(submit): restore a3c45d3b-proven config + safe improvements

Based on a3c45d3b (last known working docker build):
- yaml: max-num-seqs=2 (fixes t2_n_2), TOPK_SOFTMAX=1 (use prebuilt .so)
- yaml: keep max-model-len=131072, gpu-mem=0.90 (prevents OOM)
- yaml: NO LD_PRELOAD (libcccl not built during docker build)
- xformers: revert to Q-tiling only (flash_attn caused OOM at profiling)
- .dockerignore: exclude all non-essential files from context
- remove libcccl_allocator.so from git tracking

What stays from recent work:
- 14 prebuilt .so (including corex_gdn_chunk_recurrent)
- qwen3_5.py with .float() fix and chunk_recurrent support
- All vendor_overrides and CCCL preload source (for future use)

.dockerignore

@@ -11,3 +11,31 @@ ex_engine/
 enginex-vllm-bi100-qwen36-main.zip
 dockerrizhi.txt
 subrizhi.txt
+docs/
+optimizations/
+vllm_adapter/
+vllm_overrides/
+*.md
+verify_*.py
+verify_*.sh
+test_*.py
+debug_*.py
+probe_*.py
+probe_*.sh
+diagnose_*.sh
+cat_*.py
+attention.py
+paged_attention_v2_*.py
+paged_attn.py
+prefix_prefill.py
+engine_cccl_patterns.py
+deltanet_chunk_optimize.py
+muh_*.py
+__init__.py
+chat_dataset_v0.json
+cccl_sm100_benchmark_values.json
+baseline.muh
+launch_service
+Dockerfile.*
+computility-run.*.yaml
+computility-run.yaml.bak