Add Docker infrastructure for running TALES experiments

[MarcCote]

Docker images (vLLM + SGLang):

• docker/Dockerfile: All-in-one image based on vllm/vllm-openai:latest
• docker/Dockerfile.sglang: Alternative image based on lmsysorg/sglang:latest
• docker/entrypoint.sh: Unified entrypoint supporting both inference backends (SERVER_TYPE=vllm|sglang), activity-based startup timeout, parallel execution
• docker/README.md: Comprehensive documentation with env var reference

Local runner:

• run_experiment.sh: Launch experiments via local Docker with full CLI (--model, --server, --gpu-count, --envs, --wandb, etc.)
• .dockerignore: Whitelist-based to minimize build context

Bug fixes:

• agents/reasoning.py: Fix reasoning_effort parsed as string instead of int, add DeepSeek-V4 thinking tag extraction
• benchmark.py: Handle incomplete WandB runs in continue-from logic
• tales/token.py: Improve token counting robustness
• tales/wandb_utils.py: Better handling of missing summary data