Merge branch 'zijie/add-llama-1': Add multi-model support

- Add model registry system for dynamic model loading
- Implement LlamaForCausalLM with Llama3 RoPE scaling
- Register Qwen3ForCausalLM and Qwen2ForCausalLM
- Update ModelRunner to use get_model_class() for dynamic model selection

Tested: needle 32k test PASSED

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude/rules/gpu-testing.md

@@ -0,0 +1,88 @@
+# GPU Testing Rules
+
+## GPU Type Detection
+
+Before running any GPU test/benchmark, detect the GPU type and apply appropriate settings:
+
+```bash
+nvidia-smi --query-gpu=name --format=csv,noheader | head -1
+```
+
+### Testing Mode by GPU Type
+
+| GPU Type | Test Mode | Reason |
+|----------|-----------|--------|
+| **RTX 3090** | `--enable-offload` ONLY | Limited VRAM (24GB), must use CPU offload |
+| **A100** | Both modes OK | Large VRAM (40/80GB), can test with or without offload |
+| **RTX 4090** | `--enable-offload` ONLY | Limited VRAM (24GB) |
+| **Other** | Ask user | Unknown VRAM capacity |
+
+### Example Commands
+
+**For 3090:**
+```bash
+# MUST use offload
+CUDA_VISIBLE_DEVICES=X python tests/test_needle.py --model ~/models/Llama-3.1-8B-Instruct --enable-offload
+```
+
+**For A100:**
+```bash
+# Can test without offload
+CUDA_VISIBLE_DEVICES=X python tests/test_needle.py --model ~/models/Llama-3.1-8B-Instruct
+
+# Or with offload
+CUDA_VISIBLE_DEVICES=X python tests/test_needle.py --model ~/models/Llama-3.1-8B-Instruct --enable-offload
+```
+
+---
+
+## GPU Card Assignment (CRITICAL)
+
+### Multi-Instance Environment
+
+This project runs with multiple Claude instances on different worktrees, each needing a dedicated GPU.
+
+### MANDATORY RULE
+
+**Before executing ANY GPU command:**
+
+1. **Check if user specified GPU**: Look for user message like "use GPU 0" or "CUDA_VISIBLE_DEVICES=1"
+
+2. **If user did NOT specify GPU**:
+   - **STOP and ASK**: "Which GPU should I use? (e.g., 0, 1, 2, ...)"
+   - **DO NOT assume or guess** the GPU number
+   - **DO NOT proceed** until user confirms
+
+3. **Always prefix GPU commands with `CUDA_VISIBLE_DEVICES=X`**:
+   ```bash
+   CUDA_VISIBLE_DEVICES=0 python script.py  # Use GPU 0
+   CUDA_VISIBLE_DEVICES=1 python script.py  # Use GPU 1
+   ```
+
+### Example Workflow
+
+**Correct:**
+```
+User: "Run the needle test"
+Claude: "Which GPU should I use for this test?"
+User: "Use GPU 2"
+Claude: Runs `CUDA_VISIBLE_DEVICES=2 python tests/test_needle.py ...`
+```
+
+**Wrong:**
+```
+User: "Run the needle test"
+Claude: Runs `python tests/test_needle.py ...`  # NO! Missing GPU specification!
+```
+
+---
+
+## Combined Checklist
+
+Before running any GPU test:
+
+- [ ] User specified GPU number? If not, ASK.
+- [ ] Detected GPU type? (3090 → offload only, A100 → flexible)
+- [ ] GPU mutex check passed? (see commands.md)
+- [ ] Command prefixed with `CUDA_VISIBLE_DEVICES=X`?
+- [ ] Local package installed? (`pip install -e . --prefix=./.local --no-deps`)