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/vps.md

@@ -13,13 +13,13 @@ deployments work at a high level.
 
 ## Pick a provider
 
-- **Railway** (one‑click + browser setup): [Railway](/railway)
-- **Northflank** (one‑click + browser setup): [Northflank](/northflank)
+- **Railway** (one‑click + browser setup): [Railway](/install/railway)
+- **Northflank** (one‑click + browser setup): [Northflank](/install/northflank)
 - **Oracle Cloud (Always Free)**: [Oracle](/platforms/oracle) — $0/month (Always Free, ARM; capacity/signup can be finicky)
-- **Fly.io**: [Fly.io](/platforms/fly)
-- **Hetzner (Docker)**: [Hetzner](/platforms/hetzner)
-- **GCP (Compute Engine)**: [GCP](/platforms/gcp)
-- **exe.dev** (VM + HTTPS proxy): [exe.dev](/platforms/exe-dev)
+- **Fly.io**: [Fly.io](/install/fly)
+- **Hetzner (Docker)**: [Hetzner](/install/hetzner)
+- **GCP (Compute Engine)**: [GCP](/install/gcp)
+- **exe.dev** (VM + HTTPS proxy): [exe.dev](/install/exe-dev)
 - **AWS (EC2/Lightsail/free tier)**: works well too. Video guide:
   https://x.com/techfrenAJ/status/2014934471095812547