Add Docker containerization stack

- Dockerfile: multi-stage Python 3.13-slim, healthcheck, uvicorn CMD
- docker-compose.yml: full stack (cAIc, SearXNG, Qdrant, RabbitMQ,
  llama-server, Ollama) with healthchecks, volumes, secrets
- .dockerignore: exclude venv, tests, .git, models, secrets
- .env.example: all variables documented with generation hints
- scripts/setup.sh: first-run scaffolding (generates .env, secrets,
  SearXNG config, directories)
- searxng-settings.yml.dist: SearXNG config template
- models/README.txt: instructions for placing .gguf files
- config.py: add HW_STATE_PATH env var (CAIC_HW_STATE_PATH)
- hardware.py: read state path from config instead of hardcoded CWD
- requirements.txt: add missing psutil and jinja2

models/README.txt

@@ -0,0 +1,9 @@
+# Models
+Place .gguf model files in this directory.
+
+The filename must match the LLAMA_MODEL value in .env.
+For example, if LLAMA_MODEL=llama3.1-8b-instruct.Q4_K_M.gguf,
+place that file here.
+
+Download from HuggingFace:
+  https://huggingface.co/models?search=gguf