feat: Variet Engine v1.0 + 5-model tuning complete

Phase 01 (LLM Tuning):
- Gemma4 26B: 74.65 t/s (fast)
- Qwen 35B: 61.62 t/s (balanced)
- Gemma4 31B: 16.0 t/s (deep-coder)
- Qwen 27B: 16.7 t/s (deep-logic)
- Qwen 122B: 8.95 t/s (ultra, GPU 1 only)

Phase 02 (API Engine):
- FastAPI reverse proxy on port 8000
- /engine/switch hot-swap with 503 protection
- config/engine_models.json as single source of truth
- Replaced 4 individual .bat files with unified engine

File cleanup:
- scripts/ 85 files -> 9 + _archive/
- Root .bat files -> _archive/

scripts/_archive/results/122b_gpu1_results.json

@@ -0,0 +1,52 @@
+[
+  {
+    "name": "GPU1 only + Expert CPU + 8t",
+    "avg_tps": 8.74,
+    "best_tps": 8.75,
+    "vram_gpu0": 618,
+    "vram_gpu1": 6493,
+    "vram_total": 7111,
+    "pcie": "1, 4 | 4, 16",
+    "status": "OK"
+  },
+  {
+    "name": "GPU1 only + Expert CPU + 16t",
+    "avg_tps": 8.0,
+    "best_tps": 8.02,
+    "vram_gpu0": 619,
+    "vram_gpu1": 6493,
+    "vram_total": 7112,
+    "pcie": "1, 4 | 4, 16",
+    "status": "OK"
+  },
+  {
+    "name": "Both GPU (main=1) + Expert CPU + 8t",
+    "avg_tps": 4.71,
+    "best_tps": 4.75,
+    "vram_gpu0": 4220,
+    "vram_gpu1": 3779,
+    "vram_total": 7999,
+    "pcie": "3, 4 | 4, 16",
+    "status": "OK"
+  },
+  {
+    "name": "Both GPU (ts 0.2,0.8) + Expert CPU + 8t",
+    "avg_tps": 4.53,
+    "best_tps": 4.6,
+    "vram_gpu0": 2666,
+    "vram_gpu1": 5333,
+    "vram_total": 7999,
+    "pcie": "2, 4 | 4, 16",
+    "status": "OK"
+  },
+  {
+    "name": "GPU1 only + Expert CPU + 8t + b4096",
+    "avg_tps": 8.73,
+    "best_tps": 8.77,
+    "vram_gpu0": 615,
+    "vram_gpu1": 6895,
+    "vram_total": 7510,
+    "pcie": "1, 4 | 4, 16",
+    "status": "OK"
+  }
+]