Add dual GPU support with web UI selector

Features:
- Built custom ROCm container for AMD RX 6800 GPU
- Added GPU selection toggle in web UI (NVIDIA/AMD)
- Unified model names across both GPUs for seamless switching
- Vision model always uses NVIDIA GPU (optimal performance)
- Text models (llama3.1, darkidol) can use either GPU
- Added /gpu-status and /gpu-select API endpoints
- Implemented GPU state persistence in memory/gpu_state.json

Technical details:
- Multi-stage Dockerfile.llamaswap-rocm with ROCm 6.2.4
- llama.cpp compiled with GGML_HIP=ON for gfx1030 (RX 6800)
- Proper GPU permissions without root (groups 187/989)
- AMD container on port 8091, NVIDIA on port 8090
- Updated bot/utils/llm.py with get_current_gpu_url() and get_vision_gpu_url()
- Modified bot/utils/image_handling.py to always use NVIDIA for vision
- Enhanced web UI with GPU selector button (blue=NVIDIA, red=AMD)

Files modified:
- docker-compose.yml (added llama-swap-amd service)
- bot/globals.py (added LLAMA_AMD_URL)
- bot/api.py (added GPU selection endpoints and helper function)
- bot/utils/llm.py (GPU routing for text models)
- bot/utils/image_handling.py (GPU routing for vision models)
- bot/static/index.html (GPU selector UI)
- llama-swap-rocm-config.yaml (unified model names)

New files:
- Dockerfile.llamaswap-rocm
- bot/memory/gpu_state.json
- bot/utils/gpu_router.py (load balancing utility)
- setup-dual-gpu.sh (setup verification script)
- DUAL_GPU_*.md (documentation files)

llama-swap-rocm-config.yaml

@@ -0,0 +1,25 @@
+# llama-swap configuration for AMD RX 6800 (ROCm)
+# This manages automatic model switching and unloading for the secondary GPU
+# Vision model stays on NVIDIA GPU - AMD only handles text models
+
+models:
+  # Main text generation model (same name as NVIDIA for uniform switching)
+  llama3.1:
+    cmd: /app/llama-server --port ${PORT} --model /models/Llama-3.1-8B-Instruct-UD-Q4_K_XL.gguf -ngl 99 -nkvo -c 16384 --host 0.0.0.0 --no-warmup
+    ttl: 1800  # Unload after 30 minutes of inactivity (1800 seconds)
+    aliases:
+      - llama3.1
+      - text-model
+  
+  # Evil/Uncensored model (same name as NVIDIA for uniform switching)
+  darkidol:
+    cmd: /app/llama-server --port ${PORT} --model /models/DarkIdol-Llama-3.1-8B-Instruct-1.3-Uncensored_Q4_K_M.gguf -ngl 99 -nkvo -c 16384 --host 0.0.0.0 --no-warmup
+    ttl: 1800  # Unload after 30 minutes of inactivity
+    aliases:
+      - darkidol
+      - evil-model
+      - uncensored
+
+# Server configuration
+# llama-swap will listen on this address
+# Inside Docker, we bind to 0.0.0.0 to allow bot container to connect