docs: Restructure docs hierarchy (#83)

# Summary
Restructuring docs hierarchy and top navigation.

Signed-off-by: Alexa Haushalter <ahaushalter@nvidia.com>

Author: alexahaushalter

docs/architecture/design.md docs/developer-guide/architecture.mddocs/architecture/design.md renamed to docs/developer-guide/architecture.md

@@ -11,52 +11,70 @@ NeMo Safe Synthesizer is a comprehensive package for generating safe synthetic d
 
 ---
 
+## Key Features
+
+- **Privacy-first synthetic data** -- PII detection and replacement, optional differential privacy via Opacus
+- **LLM fine-tuning** -- LoRA fine-tuning with HuggingFace or Unsloth backends, quantization support
+- **Fast inference** -- VLLM-powered generation with structured output enforcement
+- **Comprehensive evaluation** -- Privacy metrics, quality scores, distribution analysis, and HTML reports
+- **Flexible interfaces** -- CLI for scripting, Python SDK for programmatic workflows, YAML configuration
+
+---
+
 <div class="grid cards" markdown>
 
+-   **Product Overview**
+
+    ---
+
+    Pipeline, data synthesis, PII replacement, and evaluation.
+
+    [:octicons-arrow-right-24: Product Overview](product-overview/pipeline.md)
+
 -   **Getting Started**
 
     ---
 
     Install the package, set up your environment, and run your first synthetic data pipeline in minutes.
 
-    [:octicons-arrow-right-24: Installation](getting-started/installation.md)
+    [:octicons-arrow-right-24: Getting Started](getting-started/installation.md)
+
+-   **Tutorials**
+
+    ---
+
+    Step-by-step tutorials to get you up and running.
+
+    [:octicons-arrow-right-24: Tutorials](tutorials/index.md)
 
 -   **User Guide**
 
     ---
 
-    Learn how to use the CLI, configure pipelines, and work with the Python SDK.
+    Python SDK, CLI reference, parameters, and troubleshooting.
 
-    [:octicons-arrow-right-24: User Guide](user-guide/pipeline.md)
+    [:octicons-arrow-right-24: User Guide](user-guide/sdk.md)
 
--   **Architecture**
+-   **Developer Guide**
 
     ---
 
-    Understand the pipeline design, component architecture, and key design patterns.
+    Architecture documentation and auto-generated API reference.
 
-    [:octicons-arrow-right-24: Architecture](architecture/design.md)
+    [:octicons-arrow-right-24: Developer Guide](developer-guide/architecture.md)
 
--   **API Reference**
+-   **Developer Notes**
 
     ---
 
-    Auto-generated reference documentation from source code docstrings.
+    Blog posts and release notes.
 
-    [:octicons-arrow-right-24: API Reference](reference/nemo_safe_synthesizer/sdk/library_builder.md)
+    [:octicons-arrow-right-24: Developer Notes](blog/index.md)
 
 </div>
 
 ---
 
-## Key Features
-
-- **Privacy-first synthetic data** -- PII detection and replacement, optional differential privacy via Opacus
-- **LLM fine-tuning** -- LoRA fine-tuning with HuggingFace or Unsloth backends, quantization support
-- **Fast inference** -- VLLM-powered generation with structured output enforcement
-- **Comprehensive evaluation** -- Privacy metrics, quality scores, distribution analysis, and HTML reports
-- **Flexible interfaces** -- CLI for scripting, Python SDK for programmatic workflows, YAML configuration
-
 ## Quick Example
 
 ```bash

docs/index.md

@@ -0,0 +1,3 @@
+# Data Synthesis
+
+*Add data synthesis overview and usage content here.*

docs/product-overview/data-synthesis.md

@@ -0,0 +1,3 @@
+# Troubleshooting
+
+*Add troubleshooting content here.*

docs/user-guide/evaluation.md docs/product-overview/evaluation.mddocs/user-guide/evaluation.md renamed to docs/product-overview/evaluation.md

@@ -143,20 +143,23 @@ markdown_extensions:
 
 nav:
   - Home: index.md
+  - Product Overview:
+      - Pipeline: product-overview/pipeline.md
+      - Data Synthesis: product-overview/data_synthesis.md
+      - PII Replacement: product-overview/pii_replacement.md
+      - Evaluation: product-overview/evaluation.md
   - Getting Started:
       - Installation: getting-started/installation.md
       - Quick Start: getting-started/quickstart.md
-  - User Guide:
-      - Pipeline Overview: user-guide/pipeline.md
-      - CLI Reference: user-guide/cli.md
-      - Configuration: user-guide/configuration.md
-      - Python SDK: user-guide/sdk.md
-      - Evaluation: user-guide/evaluation.md
-      - Privacy: user-guide/privacy.md
-  - Architecture:
-      - Design: architecture/design.md
   - Tutorials:
       - tutorials/index.md
-  - API Reference: reference/
-  - Dev Notes:
+  - User Guide:
+      - Python SDK: user-guide/sdk.md
+      - CLI Reference: user-guide/cli.md
+      - Parameters Reference: user-guide/parameters.md
+      - Troubleshooting: user-guide/troubleshooting.md
+  - Developer Guide:
+      - Architecture: developer-guide/architecture.md
+      - API Reference: reference/
+  - Developer Notes:
       - blog/index.md