skills: consolidate mlops redundancies (gguf+llama-cpp, grpo+trl, guidance→optional) (#11965)

Three tightly-scoped built-in skill consolidations to reduce redundancy in
the available_skills listing injected into every system prompt:

1. gguf-quantization → llama-cpp (merged)
   GGUF is llama.cpp's format; two skills covered the same toolchain. The
   merged llama-cpp skill keeps the full K-quant table + imatrix workflow
   from gguf and the ROCm/benchmarks/supported-models sections from the
   original llama-cpp. All 5 reference files preserved.

2. grpo-rl-training → fine-tuning-with-trl (folded in)
   GRPO isn't a framework, it's a trainer inside TRL. Moved the 17KB
   deep-dive SKILL.md to references/grpo-training.md and the working
   template to templates/basic_grpo_training.py. TRL's GRPO workflow
   section now points to both. Atropos skill's related_skills updated.

3. guidance → optional-skills/mlops/
   Dropped from built-in. Outlines (still built-in) covers the same
   structured-generation ground with wider adoption. Listed in the
   optional catalog for users who specifically want Guidance.

Net: 3 fewer built-in skill lines in every system prompt, zero content
loss. Contributor authorship preserved via git rename detection.

website/docs/reference/skills-catalog.md

@@ -163,10 +163,8 @@ Model serving, quantization (GGUF/GPTQ), structured output, inference optimizati
 
 | Skill | Description | Path |
 |-------|-------------|------|
-| `gguf-quantization` | GGUF format and llama.cpp quantization for efficient CPU/GPU inference. Use when deploying models on consumer hardware, Apple Silicon, or when needing flexible quantization from 2-8 bit without GPU requirements. | `mlops/inference/gguf` |
-| `guidance` | Control LLM output with regex and grammars, guarantee valid JSON/XML/code generation, enforce structured formats, and build multi-step workflows with Guidance - Microsoft Research's constrained generation framework | `mlops/inference/guidance` |
 | `instructor` | Extract structured data from LLM responses with Pydantic validation, retry failed extractions automatically, parse complex JSON with type safety, and stream partial results with Instructor - battle-tested structured output library | `mlops/inference/instructor` |
-| `llama-cpp` | Runs LLM inference on CPU, Apple Silicon, and consumer GPUs without NVIDIA hardware. Use for edge deployment, M1/M2/M3 Macs, AMD/Intel GPUs, or when CUDA is unavailable. Supports GGUF quantization (1.5-8 bit) for reduced memory and 4-10× speedup vs PyTorch on CPU. | `mlops/inference/llama-cpp` |
+| `llama-cpp` | Run LLM inference with llama.cpp on CPU, Apple Silicon, AMD/Intel GPUs, or NVIDIA — plus GGUF model conversion and quantization (2–8 bit with K-quants and imatrix). Covers CLI, Python bindings, OpenAI-compatible server, and Ollama/LM Studio integration. Use for edge deployment, M1/M2/M3/M4 Macs, CUDA-less environments, or flexible local quantization. | `mlops/inference/llama-cpp` |
 | `obliteratus` | Remove refusal behaviors from open-weight LLMs using OBLITERATUS — mechanistic interpretability techniques (diff-in-means, SVD, whitened SVD, LEACE, SAE decomposition, etc.) to excise guardrails while preserving reasoning. 9 CLI methods, 28 analysis modules, 116 model presets ac… | `mlops/inference/obliteratus` |
 | `outlines` | Guarantee valid JSON/XML/code structure during generation, use Pydantic models for type-safe outputs, support local models (Transformers, vLLM), and maximize inference speed with Outlines - dottxt.ai's structured generation library | `mlops/inference/outlines` |
 | `serving-llms-vllm` | Serves LLMs with high throughput using vLLM's PagedAttention and continuous batching. Use when deploying production LLM APIs, optimizing inference latency/throughput, or serving models with limited GPU memory. Supports OpenAI-compatible endpoints, quantization (GPTQ/AWQ/FP8), an… | `mlops/inference/vllm` |
@@ -202,7 +200,6 @@ Fine-tuning, RLHF/DPO/GRPO training, distributed training frameworks, and optimi
 | `axolotl` | Expert guidance for fine-tuning LLMs with Axolotl - YAML configs, 100+ models, LoRA/QLoRA, DPO/KTO/ORPO/GRPO, multimodal support | `mlops/training/axolotl` |
 | `distributed-llm-pretraining-torchtitan` | Provides PyTorch-native distributed LLM pretraining using torchtitan with 4D parallelism (FSDP2, TP, PP, CP). Use when pretraining Llama 3.1, DeepSeek V3, or custom models at scale from 8 to 512+ GPUs with Float8, torch.compile, and distributed checkpointing. | `mlops/training/torchtitan` |
 | `fine-tuning-with-trl` | Fine-tune LLMs using reinforcement learning with TRL - SFT for instruction tuning, DPO for preference alignment, PPO/GRPO for reward optimization, and reward model training. Use when need RLHF, align model with preferences, or train from human feedback. Works with HuggingFace Tr… | `mlops/training/trl-fine-tuning` |
-| `grpo-rl-training` | Expert guidance for GRPO/RL fine-tuning with TRL for reasoning and task-specific model training | `mlops/training/grpo-rl-training` |
 | `hermes-atropos-environments` | Build, test, and debug Hermes Agent RL environments for Atropos training. Covers the HermesAgentBaseEnv interface, reward functions, agent loop integration, evaluation with tools, wandb logging, and the three CLI modes (serve/process/evaluate). Use when creating, reviewing, or f… | `mlops/training/hermes-atropos-environments` |
 | `huggingface-accelerate` | Simplest distributed training API. 4 lines to add distributed support to any PyTorch script. Unified API for DeepSpeed/FSDP/Megatron/DDP. Automatic device placement, mixed precision (FP16/BF16/FP8). Interactive config, single launch command. HuggingFace ecosystem standard. | `mlops/training/accelerate` |
 | `optimizing-attention-flash` | Optimizes transformer attention with Flash Attention for 2-4x speedup and 10-20x memory reduction. Use when training/running transformers with long sequences (>512 tokens), encountering GPU memory issues with attention, or need faster inference. Supports PyTorch native SDPA,… | `mlops/training/flash-attention` |