docs: restructure Get Started tab and improve onboarding flow (#9950)

* docs: restructure Get Started tab and improve onboarding flow

- Flatten nested Onboarding group into linear First Steps flow
- Add 'What is OpenClaw?' narrative section to landing page
- Split wizard.md into streamlined overview + full reference (reference/wizard.md)
- Move Pairing to Channels > Configuration
- Move Bootstrapping to Agents > Fundamentals
- Move macOS app onboarding to Platforms > macOS companion app
- Move Lore to Help > Community
- Remove duplicate install instructions from openclaw.md
- Mirror navigation changes in zh-CN tabs
- No content deleted — all detail preserved or relocated

* docs: move deployment pages to install/, fix Platforms tab routing, clarify onboarding paths

- Move deployment guides (fly, hetzner, gcp, macos-vm, exe-dev, railway, render,
  northflank) from platforms/ and root to install/
- Add 'Hosting and deployment' group to Install tab
- Slim Gateway & Ops 'Remote access and deployment' down to 'Remote access'
- Swap Platforms tab before Gateway & Ops to fix path-prefix routing
- Move macOS app onboarding into First steps (parallel to CLI wizard)
- Rename sidebar titles to 'Onboarding: CLI' / 'Onboarding: macOS App'
- Add redirects for all moved paths
- Update all internal links (en + zh-CN)
- Fix img tag syntax in onboarding.md

docs/index.md

@@ -41,7 +41,20 @@ title: "OpenClaw"
   </Card>
 </Columns>
 
-OpenClaw connects chat apps to coding agents like Pi through a single Gateway process. It powers the OpenClaw assistant and supports local or remote setups.
+## What is OpenClaw?
+
+OpenClaw is a **self-hosted gateway** that connects your favorite chat apps — WhatsApp, Telegram, Discord, iMessage, and more — to AI coding agents like Pi. You run a single Gateway process on your own machine (or a server), and it becomes the bridge between your messaging apps and an always-available AI assistant.
+
+**Who is it for?** Developers and power users who want a personal AI assistant they can message from anywhere — without giving up control of their data or relying on a hosted service.
+
+**What makes it different?**
+
+- **Self-hosted**: runs on your hardware, your rules
+- **Multi-channel**: one Gateway serves WhatsApp, Telegram, Discord, and more simultaneously
+- **Agent-native**: built for coding agents with tool use, sessions, memory, and multi-agent routing
+- **Open source**: MIT licensed, community-driven
+
+**What do you need?** Node 22+, an API key (Anthropic recommended), and 5 minutes.
 
 ## How it works