Code review and fixes.

docs/testing/wine-proton.md

@@ -59,6 +59,25 @@ selection, staging, and environment forwarding are covered by
 not establish compatibility with a real Proton runtime or audible
 Wine output.
 
+Helper readiness is published from bounded stderr input before diagnostic
+throttling or log delivery, so a diagnostic burst or stalled log sink cannot
+discard the exclusion count needed for fallback. Configuration, preferences,
+and helper launch use the same executable-name validation, including rejection
+of embedded control characters. Regression checks:
+
+```sh
+go test ./internal/wine ./internal/config ./internal/preferences -count=1
+```
+
+The private Wine preferences check also exercises pasting an embedded tab,
+blocking Apply, deleting the invalid row, and applying valid entries. It needs
+`xclip` for the private clipboard:
+
+```sh
+go build -o /tmp/cthulhu-wine-check ./cmd/cthulhu
+CTHULHU_BINARY=/tmp/cthulhu-wine-check CTHULHU_PREFS_WINE_ONLY=1 python3 tests/native_preferences.py
+```
+
 Two statements in that parallel document described pre-stage
 behaviour and are **not** carried forward: Wine settings no longer
 require a reader restart (a global preferences Apply republishes