feat(analytics): connect Umami analytics across www, docs, and static services (#49)

## Summary of Changes

- **`@ermnvldmr/ssg`**: Added extensible `AnalyticsProvider` interface,
`umamiAnalytics` integration in `@ermnvldmr/ssg/dev`, and runtime client
analytics dispatchers (`trackEvent`, `identifySession`).
- **`services/docs`**: Configured native Hextra Umami parameters in
`hugo.yaml` (`docs.ermnvldmr.com` with UUID
`fbdadf3f-3484-4186-a2c2-cedcf76cf44f`).
- **`services/www`**: Injected Umami tracking provider into
`rsbuild.config.ts` (`ermnvldmr.com`, `www.ermnvldmr.com` with UUID
`4fca5ac2-4fe4-4626-b708-933c37bfe918`).
- **`services/static`**: Injected Umami tracking provider into
`rsbuild.config.ts` (`static.ermnvldmr.com` with UUID
`0831532a-2cec-4955-8f5b-452d8bba96d8`).
- **Environment & Privacy**: Injections are automatically disabled in
development builds. Configured `data-domains` filtering and
`data-do-not-track="true"`.

## Verification
- `pnpm typecheck`: Passed (0 errors)
- `pnpm lint`: Passed (0 warnings)
- `pnpm test`: Passed (all unit test suites)
- `pnpm build`: Passed clean workspace build and pre-rendered SSG
injection

---
Disclosure: I'm an AI assistant helping Vladimir Eremin; I'm not
Vladimir Eremin.

services/docs/hugo.yaml

@@ -45,6 +45,14 @@ params:
     email: personal@ermnvldmr.com
   description: 'Documentation for ermnvldmr.com services and infrastructure'
 
+  # Analytics configuration
+  analytics:
+    umami:
+      serverURL: 'https://umami.ermnvldmr.com'
+      websiteID: 'fbdadf3f-3484-4186-a2c2-cedcf76cf44f'
+      domains: 'docs.ermnvldmr.com'
+      doNotTrack: 'true'
+
   # Search configuration
   search:
     enable: true