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

tests/unit/web/analytics.test.ts

@@ -319,7 +319,7 @@ describe("analytics lib", () => {
       setAnalyticsConsent(true);
       await initAnalytics(enabledConfig);
       identify("inst-1", { version: "1.0" });
-      expect(mockIdentify).toHaveBeenCalledWith("inst-1", { version: "1.0" });
+      expect(mockIdentify).toHaveBeenCalledWith("inst-1", { version: "1.0" }, undefined);
     });
 
     it("does not throw before initialization", () => {
@@ -382,7 +382,7 @@ describe("analytics lib", () => {
       track("phase1_event");
       expect(mockCapture).toHaveBeenCalledWith("phase1_event", undefined);
       identify("inst-1", { phase: 1 });
-      expect(mockIdentify).toHaveBeenCalledWith("inst-1", { phase: 1 });
+      expect(mockIdentify).toHaveBeenCalledWith("inst-1", { phase: 1 }, undefined);
 
       // Phase 2: Revoke consent mid-session
       setAnalyticsConsent(false);