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/image-engine/operations.test.ts

@@ -229,13 +229,12 @@ describe("resize", () => {
     expect(meta.width).toBeGreaterThanOrEqual(0);
   });
 
-  it("percentage=1 on 1x1 yields width rounded to 0 and triggers error", async () => {
-    // 1 * 1/100 = 0.01 -> Math.round -> 0
-    // Then the check width <= 0 should throw
+  it("percentage=1 on 1x1 clamps to 1px minimum", async () => {
     const img = sharp(png1x1);
-    await expect(resize(img, { percentage: 1 })).rejects.toThrow(
-      "Resize width must be greater than 0",
-    );
+    const result = await resize(img, { percentage: 1 });
+    const meta = await result.toBuffer().then((b) => sharp(b).metadata());
+    expect(meta.width).toBe(1);
+    expect(meta.height).toBe(1);
   });
 });