refactor(common): consolidate analytics (Commit 2.8)

Consolidates analytics utilities into a dedicated directory structure:
- common/src/analytics/index.ts: Unified re-exports
- common/src/analytics/core.ts: PostHog client factory, types
- common/src/analytics/dispatcher.ts: Cross-platform event dispatcher with buffering
- common/src/analytics/log-helpers.ts: Log data conversion, PII filtering
- common/src/analytics/track-event.ts: Server-side tracking with lazy client init

Key features:
- PII filtering with allowlist/blocklist approach
- MAX_BUFFER_SIZE=100 prevents unbounded memory growth
- Lazy PostHog client initialization in production only
- resetAnalyticsClient() helper exported for testing

Comprehensive unit tests added:
- track-event.test.ts: 16 tests for trackEvent, flushAnalytics, resetAnalyticsClient
- Tests cover lazy init, error handling, env gating, edge cases (empty userId)

Author: brandonkachen

cli/src/utils/__tests__/analytics-client.test.ts

@@ -2,7 +2,7 @@ import { describe, test, expect, beforeEach, mock } from 'bun:test'
 
 import { AnalyticsEvent } from '@codebuff/common/constants/analytics-events'
 
-import type { AnalyticsClientWithIdentify } from '@codebuff/common/analytics-core'
+import type { AnalyticsClientWithIdentify } from '@codebuff/common/analytics'
 
 import {
   initAnalytics,

cli/src/utils/analytics.ts

@@ -3,7 +3,7 @@ import {
   generateAnonymousId,
   type AnalyticsClientWithIdentify,
   type PostHogClientOptions,
-} from '@codebuff/common/analytics-core'
+} from '@codebuff/common/analytics'
 import {
   env as defaultEnv,
   IS_PROD as defaultIsProd,
@@ -14,7 +14,7 @@ import type { AnalyticsEvent } from '@codebuff/common/constants/analytics-events
 
 
 // Re-export types from core for backwards compatibility
-export type { AnalyticsClientWithIdentify as AnalyticsClient } from '@codebuff/common/analytics-core'
+export type { AnalyticsClientWithIdentify as AnalyticsClient } from '@codebuff/common/analytics'
 
 export enum AnalyticsErrorStage {
   Init = 'init',

cli/src/utils/logger.ts

@@ -4,9 +4,9 @@ import { format as stringFormat } from 'util'
 import { pino } from 'pino'
 
 import { env, IS_DEV, IS_TEST, IS_CI } from '@codebuff/common/env'
-import { createAnalyticsDispatcher } from '@codebuff/common/util/analytics-dispatcher'
+import { createAnalyticsDispatcher } from '@codebuff/common/analytics'
 import { AnalyticsEvent } from '@codebuff/common/constants/analytics-events'
-import { getAnalyticsEventId } from '@codebuff/common/util/analytics-log'
+import { getAnalyticsEventId } from '@codebuff/common/analytics'
 
 import {
   flushAnalytics,