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/start/onboarding.md

@@ -4,7 +4,7 @@ read_when:
   - Designing the macOS onboarding assistant
   - Implementing auth or identity setup
 title: "Onboarding (macOS App)"
-sidebarTitle: "macOS app"
+sidebarTitle: "Onboarding: macOS App"
 ---
 
 # Onboarding (macOS App)
@@ -16,22 +16,22 @@ wizard, and let the agent bootstrap itself.
 <Steps>
 <Step title="Approve macOS warning">
 <Frame>
-<img src="/assets/macos-onboarding/01-macos-warning.jpeg" alt=""></img>
+<img src="/assets/macos-onboarding/01-macos-warning.jpeg" alt="" />
 </Frame>
 </Step>
 <Step title="Approve find local networks">
 <Frame>
-<img src="/assets/macos-onboarding/02-local-networks.jpeg" alt=""></img>
+<img src="/assets/macos-onboarding/02-local-networks.jpeg" alt="" />
 </Frame>
 </Step>
 <Step title="Welcome and security notice">
 <Frame caption="Read the security notice displayed and decide accordingly">
-<img src="/assets/macos-onboarding/03-security-notice.png" alt=""></img>
+<img src="/assets/macos-onboarding/03-security-notice.png" alt="" />
 </Frame>
 </Step>
 <Step title="Local vs Remote">
 <Frame>
-<img src="/assets/macos-onboarding/04-choose-gateway.png" alt=""></img>
+<img src="/assets/macos-onboarding/04-choose-gateway.png" alt="" />
 </Frame>
 
 Where does the **Gateway** run?
@@ -51,7 +51,7 @@ Where does the **Gateway** run?
 </Step>
 <Step title="Permissions">
 <Frame caption="Choose what permissions do you want to give OpenClaw">
-<img src="/assets/macos-onboarding/05-permissions.png" alt=""></img>
+<img src="/assets/macos-onboarding/05-permissions.png" alt="" />
 </Frame>
 
 Onboarding requests TCC permissions needed for: