Write down what actually made a UI test go red

The earlier entry said only "suspect what the test does not control".
Having now found it, the specifics are worth more than the warning.

State leaks between UI tests because @AppStorage is UserDefaults and the
simulator keeps them for days; the fix is a debug hook writing to the
normal domain, because launch arguments land in NSArgumentDomain and
outrank the app, making settings unchangeable rather than merely
predictable. Elements below the fold of a lazy container genuinely do not
exist, which reads exactly like a bug. Both cost a full evening.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.claude-plugin/marketplace.json

@@ -12,7 +12,7 @@
       "name": "pdat-swift-practice",
       "source": "./pdat-swift-practice",
       "description": "Curated Apple platform findings with sources, plus practices learned from production incidents.",
-      "version": "0.3.0",
+      "version": "0.4.0",
       "author": {
         "name": "PDAT s.r.o."
       },