docs: consolidate getting started documentation

Rename onboarding-guide.md to getting-started.md for consistency across
Socket repos. Update README and docs index to reference both the quick
start (10 min) and detailed development guide, giving contributors clear
entry points.

Changes:
- Rename docs/onboarding-guide.md → docs/getting-started.md
- Update title from "Onboarding Guide" to "Getting Started"
- Add quick start reference to main README Contributing section
- Update docs/README.md to show both quick and detailed paths

Author: jdalton

README.md

@@ -100,7 +100,10 @@ Supports version 2 format with `projectIgnorePaths` for excluding files from rep
 
 ## Contributing
 
-**New to Socket CLI development?** Start with our [Getting Started Guide](docs/development/getting-started.md) for complete setup instructions.
+**New to Socket CLI development?**
+
+- **Quick Start (10 min)**: [Getting Started Guide](docs/getting-started.md) — Essential setup and first contribution
+- **Detailed Guide**: [Development Getting Started](docs/development/getting-started.md) — Complete end-to-end onboarding
 
 **Quick setup:**
 

docs/README.md

@@ -2,11 +2,13 @@
 
 ## New to Socket CLI Development?
 
-**Start here:** [Getting Started Guide](development/getting-started.md)
+**Choose your path:**
 
-Complete end-to-end onboarding for new contributors:
+- **[Quick Start (10 min)](getting-started.md)** — Essential setup and first contribution
+- **[Detailed Guide](development/getting-started.md)** — Complete end-to-end onboarding with troubleshooting
+
+The detailed guide includes:
 - Prerequisites and installation
-- 5-minute quick start
 - Development workflow
 - Testing strategies
 - Troubleshooting guide

docs/onboarding-guide.md renamed to docs/getting-started.md

@@ -1,6 +1,6 @@
-# Onboarding Guide
+# Getting Started
 
-**New Contributor Quickstart** — Get started with Socket CLI development in 10 minutes.
+**Quick start guide** — Get started with Socket CLI development in 10 minutes.
 
 ---