docs: Reorganize documentation on the webpage (#2651)

# What does this PR do?
Reorganizes the Llama stack webpage into more concise index pages,
introduce more of a workflow, and reduce repetition of content.

New nav structure so far based on #2637 

Further discussions in
https://github.com/meta-llama/llama-stack/discussions/2585

**Preview:**
![Screenshot 2025-07-09 at 2 31
53 PM](https://github.com/user-attachments/assets/4c1f3845-b328-4f12-9f20-3f09375007af)

You can also build a full local preview locally 

 **Feedback**
Looking for feedback on page titles and general feedback on the new
structure

**Follow up documentation**
I plan on reducing some sections and standardizing some terminology in a
follow up PR.
More discussions on that in
https://github.com/meta-llama/llama-stack/discussions/2585

docs/source/providers/post_training/huggingface.md

@@ -1,122 +0,0 @@
----
-orphan: true
----
-# HuggingFace SFTTrainer
-
-[HuggingFace SFTTrainer](https://huggingface.co/docs/trl/en/sft_trainer) is an inline post training provider for Llama Stack. It allows you to run supervised fine tuning on a variety of models using many datasets
-
-## Features
-
-- Simple access through the post_training API
-- Fully integrated with Llama Stack
-- GPU support, CPU support, and MPS support (MacOS Metal Performance Shaders)
-
-## Usage
-
-To use the HF SFTTrainer in your Llama Stack project, follow these steps:
-
-1. Configure your Llama Stack project to use this provider.
-2. Kick off a SFT job using the Llama Stack post_training API.
-
-## Setup
-
-You can access the HuggingFace trainer via the `ollama` distribution:
-
-```bash
-llama stack build --template starter --image-type venv
-llama stack run --image-type venv ~/.llama/distributions/ollama/ollama-run.yaml
-```
-
-## Run Training
-
-You can access the provider and the `supervised_fine_tune` method via the post_training API:
-
-```python
-import time
-import uuid
-
-
-from llama_stack_client.types import (
-    post_training_supervised_fine_tune_params,
-    algorithm_config_param,
-)
-
-
-def create_http_client():
-    from llama_stack_client import LlamaStackClient
-
-    return LlamaStackClient(base_url="http://localhost:8321")
-
-
-client = create_http_client()
-
-# Example Dataset
-client.datasets.register(
-    purpose="post-training/messages",
-    source={
-        "type": "uri",
-        "uri": "huggingface://datasets/llamastack/simpleqa?split=train",
-    },
-    dataset_id="simpleqa",
-)
-
-training_config = post_training_supervised_fine_tune_params.TrainingConfig(
-    data_config=post_training_supervised_fine_tune_params.TrainingConfigDataConfig(
-        batch_size=32,
-        data_format="instruct",
-        dataset_id="simpleqa",
-        shuffle=True,
-    ),
-    gradient_accumulation_steps=1,
-    max_steps_per_epoch=0,
-    max_validation_steps=1,
-    n_epochs=4,
-)
-
-algorithm_config = algorithm_config_param.LoraFinetuningConfig(  # this config is also currently mandatory but should not be
-    alpha=1,
-    apply_lora_to_mlp=True,
-    apply_lora_to_output=False,
-    lora_attn_modules=["q_proj"],
-    rank=1,
-    type="LoRA",
-)
-
-job_uuid = f"test-job{uuid.uuid4()}"
-
-# Example Model
-training_model = "ibm-granite/granite-3.3-8b-instruct"
-
-start_time = time.time()
-response = client.post_training.supervised_fine_tune(
-    job_uuid=job_uuid,
-    logger_config={},
-    model=training_model,
-    hyperparam_search_config={},
-    training_config=training_config,
-    algorithm_config=algorithm_config,
-    checkpoint_dir="output",
-)
-print("Job: ", job_uuid)
-
-
-# Wait for the job to complete!
-while True:
-    status = client.post_training.job.status(job_uuid=job_uuid)
-    if not status:
-        print("Job not found")
-        break
-
-    print(status)
-    if status.status == "completed":
-        break
-
-    print("Waiting for job to complete...")
-    time.sleep(5)
-
-end_time = time.time()
-print("Job completed in", end_time - start_time, "seconds!")
-
-print("Artifacts:")
-print(client.post_training.job.artifacts(job_uuid=job_uuid))
-```

docs/source/providers/post_training/nvidia_nemo.md

@@ -1,163 +0,0 @@
----
-orphan: true
----
-# NVIDIA NEMO
-
-[NVIDIA NEMO](https://developer.nvidia.com/nemo-framework) is a remote post training provider for Llama Stack. It provides enterprise-grade fine-tuning capabilities through NVIDIA's NeMo Customizer service.
-
-## Features
-
-- Enterprise-grade fine-tuning capabilities
-- Support for LoRA and SFT fine-tuning
-- Integration with NVIDIA's NeMo Customizer service
-- Support for various NVIDIA-optimized models
-- Efficient training with NVIDIA hardware acceleration
-
-## Usage
-
-To use NVIDIA NEMO in your Llama Stack project, follow these steps:
-
-1. Configure your Llama Stack project to use this provider.
-2. Set up your NVIDIA API credentials.
-3. Kick off a fine-tuning job using the Llama Stack post_training API.
-
-## Setup
-
-You'll need to set the following environment variables:
-
-```bash
-export NVIDIA_API_KEY="your-api-key"
-export NVIDIA_DATASET_NAMESPACE="default"
-export NVIDIA_CUSTOMIZER_URL="your-customizer-url"
-export NVIDIA_PROJECT_ID="your-project-id"
-export NVIDIA_OUTPUT_MODEL_DIR="your-output-model-dir"
-```
-
-## Run Training
-
-You can access the provider and the `supervised_fine_tune` method via the post_training API:
-
-```python
-import time
-import uuid
-
-from llama_stack_client.types import (
-    post_training_supervised_fine_tune_params,
-    algorithm_config_param,
-)
-
-
-def create_http_client():
-    from llama_stack_client import LlamaStackClient
-
-    return LlamaStackClient(base_url="http://localhost:8321")
-
-
-client = create_http_client()
-
-# Example Dataset
-client.datasets.register(
-    purpose="post-training/messages",
-    source={
-        "type": "uri",
-        "uri": "huggingface://datasets/llamastack/simpleqa?split=train",
-    },
-    dataset_id="simpleqa",
-)
-
-training_config = post_training_supervised_fine_tune_params.TrainingConfig(
-    data_config=post_training_supervised_fine_tune_params.TrainingConfigDataConfig(
-        batch_size=8,  # Default batch size for NEMO
-        data_format="instruct",
-        dataset_id="simpleqa",
-        shuffle=True,
-    ),
-    n_epochs=50,  # Default epochs for NEMO
-    optimizer_config=post_training_supervised_fine_tune_params.TrainingConfigOptimizerConfig(
-        lr=0.0001,  # Default learning rate
-        weight_decay=0.01,  # NEMO-specific parameter
-    ),
-    # NEMO-specific parameters
-    log_every_n_steps=None,
-    val_check_interval=0.25,
-    sequence_packing_enabled=False,
-    hidden_dropout=None,
-    attention_dropout=None,
-    ffn_dropout=None,
-)
-
-algorithm_config = algorithm_config_param.LoraFinetuningConfig(
-    alpha=16,  # Default alpha for NEMO
-    type="LoRA",
-)
-
-job_uuid = f"test-job{uuid.uuid4()}"
-
-# Example Model - must be a supported NEMO model
-training_model = "meta/llama-3.1-8b-instruct"
-
-start_time = time.time()
-response = client.post_training.supervised_fine_tune(
-    job_uuid=job_uuid,
-    logger_config={},
-    model=training_model,
-    hyperparam_search_config={},
-    training_config=training_config,
-    algorithm_config=algorithm_config,
-    checkpoint_dir="output",
-)
-print("Job: ", job_uuid)
-
-# Wait for the job to complete!
-while True:
-    status = client.post_training.job.status(job_uuid=job_uuid)
-    if not status:
-        print("Job not found")
-        break
-
-    print(status)
-    if status.status == "completed":
-        break
-
-    print("Waiting for job to complete...")
-    time.sleep(5)
-
-end_time = time.time()
-print("Job completed in", end_time - start_time, "seconds!")
-
-print("Artifacts:")
-print(client.post_training.job.artifacts(job_uuid=job_uuid))
-```
-
-## Supported Models
-
-Currently supports the following models:
-- meta/llama-3.1-8b-instruct
-- meta/llama-3.2-1b-instruct
-
-## Supported Parameters
-
-### TrainingConfig
-- n_epochs (default: 50)
-- data_config
-- optimizer_config
-- log_every_n_steps
-- val_check_interval (default: 0.25)
-- sequence_packing_enabled (default: False)
-- hidden_dropout (0.0-1.0)
-- attention_dropout (0.0-1.0)
-- ffn_dropout (0.0-1.0)
-
-### DataConfig
-- dataset_id
-- batch_size (default: 8)
-
-### OptimizerConfig
-- lr (default: 0.0001)
-- weight_decay (default: 0.01)
-
-### LoRA Config
-- alpha (default: 16)
-- type (must be "LoRA")
-
-Note: Some parameters from the standard Llama Stack API are not supported and will be ignored with a warning.

docs/source/providers/post_training/torchtune.md

@@ -1,125 +0,0 @@
----
-orphan: true
----
-# TorchTune
-
-[TorchTune](https://github.com/pytorch/torchtune) is an inline post training provider for Llama Stack. It provides a simple and efficient way to fine-tune language models using PyTorch.
-
-## Features
-
-- Simple access through the post_training API
-- Fully integrated with Llama Stack
-- GPU support and single device capabilities.
-- Support for LoRA
-
-## Usage
-
-To use TorchTune in your Llama Stack project, follow these steps:
-
-1. Configure your Llama Stack project to use this provider.
-2. Kick off a fine-tuning job using the Llama Stack post_training API.
-
-## Setup
-
-You can access the TorchTune trainer by writing your own yaml pointing to the provider:
-
-```yaml
-post_training:
-  - provider_id: torchtune
-    provider_type: inline::torchtune
-    config: {}
-```
-
-you can then build and run your own stack with this provider.
-
-## Run Training
-
-You can access the provider and the `supervised_fine_tune` method via the post_training API:
-
-```python
-import time
-import uuid
-
-from llama_stack_client.types import (
-    post_training_supervised_fine_tune_params,
-    algorithm_config_param,
-)
-
-
-def create_http_client():
-    from llama_stack_client import LlamaStackClient
-
-    return LlamaStackClient(base_url="http://localhost:8321")
-
-
-client = create_http_client()
-
-# Example Dataset
-client.datasets.register(
-    purpose="post-training/messages",
-    source={
-        "type": "uri",
-        "uri": "huggingface://datasets/llamastack/simpleqa?split=train",
-    },
-    dataset_id="simpleqa",
-)
-
-training_config = post_training_supervised_fine_tune_params.TrainingConfig(
-    data_config=post_training_supervised_fine_tune_params.TrainingConfigDataConfig(
-        batch_size=32,
-        data_format="instruct",
-        dataset_id="simpleqa",
-        shuffle=True,
-    ),
-    gradient_accumulation_steps=1,
-    max_steps_per_epoch=0,
-    max_validation_steps=1,
-    n_epochs=4,
-)
-
-algorithm_config = algorithm_config_param.LoraFinetuningConfig(
-    alpha=1,
-    apply_lora_to_mlp=True,
-    apply_lora_to_output=False,
-    lora_attn_modules=["q_proj"],
-    rank=1,
-    type="LoRA",
-)
-
-job_uuid = f"test-job{uuid.uuid4()}"
-
-# Example Model
-training_model = "meta-llama/Llama-2-7b-hf"
-
-start_time = time.time()
-response = client.post_training.supervised_fine_tune(
-    job_uuid=job_uuid,
-    logger_config={},
-    model=training_model,
-    hyperparam_search_config={},
-    training_config=training_config,
-    algorithm_config=algorithm_config,
-    checkpoint_dir="output",
-)
-print("Job: ", job_uuid)
-
-# Wait for the job to complete!
-while True:
-    status = client.post_training.job.status(job_uuid=job_uuid)
-    if not status:
-        print("Job not found")
-        break
-
-    print(status)
-    if status.status == "completed":
-        break
-
-    print("Waiting for job to complete...")
-    time.sleep(5)
-
-end_time = time.time()
-print("Job completed in", end_time - start_time, "seconds!")
-
-print("Artifacts:")
-print(client.post_training.job.artifacts(job_uuid=job_uuid))
-```