refactor(apps/*,docs): unify PostHog config (#875)

* refactor(apps/*,docs): unify PostHog config

* [autofix.ci] apply automated fixes

* refactor: remove ImportMeta and keep ImportMetaEnv only

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

docs/.vitepress/modules/posthog.ts

@@ -1,6 +1,8 @@
 import posthog from 'posthog-js'
 
-posthog.init('phc_pzjziJjrVZpa9SqnQqq0QEKvkmuCPH7GDTA6TbRTEf9', {
-  api_host: 'https://us.i.posthog.com',
-  person_profiles: 'identified_only', // or 'always' to create profiles for anonymous users as well
+import { DEFAULT_POSTHOG_CONFIG, POSTHOG_PROJECT_KEY_DOCS } from '../../../posthog.config'
+
+posthog.init(POSTHOG_PROJECT_KEY_DOCS, {
+  ...DEFAULT_POSTHOG_CONFIG,
+  // Project-specific config...
 })