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/dual_gpu_summary.txt

@@ -0,0 +1,31 @@
+Dual-GPU Benchmark v2 — 2026-04-06T06:52:08.868Z
+2x RTX 3060 12GB | 256K Context | 58 configs | 69.4 min
+
+=======================================================
+  RANKING
+=======================================================
+
+  🥇 #1: Gemma4-26B Q4_K_M
+      AVG: 76.4 t/s | BEST: 76.75 t/s | Boot: 9s
+      ngl=999 t=6 ub=512 b=2048 ctk=f16 ctv=f16
+
+  🥈 #2: Gemma4-26B MXFP4_MOE
+      AVG: 64.05 t/s | BEST: 64.29 t/s | Boot: 9s
+      ngl=999 t=2 ub=512 b=2048 ctk=q8_0 ctv=q8_0
+
+  🥉 #3: Qwen3.5-35B Q4_K_M
+      AVG: 52.05 t/s | BEST: 54.48 t/s | Boot: 12.1s
+      ngl=999 t=4 ub=256 b=1024 ctk=q4_0 ctv=q4_0
+      --n-cpu-moe 5
+
+     #4: Qwen3.5-35B MXFP4_MOE
+      AVG: 46.66 t/s | BEST: 47.09 t/s | Boot: 15s
+      ngl=999 t=6 ub=512 b=2048 ctk=q4_0 ctv=q4_0
+      --n-cpu-moe 5
+
+=======================================================
+  ★ CHAMPION: Gemma4-26B Q4_K_M — 76.4 t/s
+=======================================================
+
+  Recommended:
+    llama-server --model models\gemma-4-26B-A4B-it-Q4_K_M.gguf -ngl 999 -c 262144 -t 6 -tb 6 -ub 512 -b 2048 -fa on --cache-type-k f16 --cache-type-v f16 --prio 3 --poll 50 --mlock --port 8000 --host 0.0.0.0