feat(docs): add Google Analytics with privacy-compliant cookie consent (#174)

## Summary

Adds Google Analytics tracking to the OpenTDF documentation site with
full GDPR/CCPA compliance through:
- Opt-in cookie consent banner
- Privacy Policy, Cookie Policy, and Terms of Service pages (leveraging
Virtru's legal language)
- Legal section in footer

## Changes

- ✅ Cookie consent banner using `react-cookie-consent`
  - Only loads Google Analytics after user accepts cookies
  - Decline option available
  - Preference saved for 365 days
- ✅ IP anonymization enabled for GDPR compliance
- ✅ Privacy Policy page (`/privacy-policy`)
- ✅ Cookie Policy page (`/cookie-policy`)
- ✅ Terms of Service page (`/terms-of-service`)
- ✅ Legal footer section with links to all policy pages
- ✅ Fix: Getting Started page title in sidebar (was showing "index")

## Privacy & Legal Compliance

- **GDPR Compliant**: Opt-in consent, IP anonymization, user rights
documented
- **CCPA Compliant**: Privacy policy includes California resident rights
- **No Personal Data Sales**: Explicit commitment in policies
- **Contact Information**: Uses Virtru contact details
([email protected])


## Testing

- ✅ Build succeeds locally
- ✅ Cookie banner appears on first visit
- ✅ Analytics only loads after acceptance
- ✅ All policy pages render correctly
- ✅ Footer links work
- ✅ No broken links or build warnings

## Screenshots

The cookie consent banner appears at the bottom of all pages with
Accept/Decline options and links to privacy policies.

---

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Sonnet 4.5 <[email protected]>

Author: jp-ayyappan

docs/getting-started/index.mdx

@@ -1,5 +1,7 @@
 ---
 slug: /getting-started
+title: Getting Started
+sidebar_label: Getting Started
 ---
 
 import dockerComposeContent from '!!raw-loader!./docker-compose.yaml';

docusaurus.config.ts

@@ -36,6 +36,7 @@ const config: Config = {
   trailingSlash: false,
   customFields: {
     javaSdkVersion,
+    googleGtagId: 'G-JH0PNJK88L',
   },
 
   // GitHub pages deployment config.
@@ -178,6 +179,23 @@ const config: Config = {
             },
           ],
         },
+        {
+          title: "Legal",
+          items: [
+            {
+              label: "Privacy Policy",
+              to: "/privacy-policy",
+            },
+            {
+              label: "Cookie Policy",
+              to: "/cookie-policy",
+            },
+            {
+              label: "Terms of Service",
+              to: "/terms-of-service",
+            },
+          ],
+        },
       ],
       copyright: `
           <span>Copyright © ${new Date().getFullYear()} OpenTDF</span>