fix: resolve analytics data gaps and resize validation failures

- Fix resize 20% failure rate: add Zod refine requiring at least one
  dimension, enforce integer/max constraints, clamp percentage scaling
  to minimum 1px, and guard against missing metadata in withoutEnlargement
- Fix PostHog init race condition: move consent check before async import
  so frontend events (search, pageview) are no longer silently dropped
- Fix identify() passing nested $set/$set_once wrappers instead of flat
  properties, so version person property now appears on PostHog profiles
- Add error_code and error_message to failed tool_used analytics events
  for debugging tool failures from PostHog

packages/shared/src/analytics/events.ts

@@ -14,6 +14,8 @@ export interface ToolUsedProperties {
   category: string;
   is_ai_tool: boolean;
   params?: Record<string, string | number | boolean>;
+  error_code?: string;
+  error_message?: string;
 }
 
 export interface SearchProperties {