docs: file #400 (Credits -> gmCreditsUI, post-LA) and fix the misfiled comment

The ef96c554 batch ghosted Credits with a comment claiming it was filed
as #397 - that number is the Windows graceful-stop issue and no Credits
entry existed. #400 now records the gap properly.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/ISSUES.md

@@ -24,6 +24,25 @@ What does NOT go here:
 - Every session: scan OPEN issues at start; promote/close anything we touched during the session before ending.
 - Promoting to a Phase: mark as `DONE (promoted to Phase X)` + commit SHA where the Phase entry landed.
 
+## #400 — Character select: Credits button is ghosted; retail opens gmCreditsUI
+
+**Status:** OPEN (post-LA polish)
+**Severity:** LOW
+**Filed:** 2026-08-15 (Campaign LA gate round 2, char-select findings batch)
+**Component:** `src/AcDream.App/UI/Layout/CharacterManagementUiController.cs`
+
+Retail's character-management screen routes the Credits button
+(`0x100003A3`, listbox-base offset 6 in
+`gmCharacterManagementUI::ListenToElementMessage @0x004ed5a0`) to
+`QueueUIMode(0x10000005)` → `gmCreditsUI` (`Register @0x0047a69e`) — a
+scrolling credits screen. acdream ghosts the button (visible, disabled,
+no invented action — the same treatment as Create Character). Porting
+`gmCreditsUI` is its own small screen (authored layout, scroll behavior,
+return-to-select) and is deliberately out of Campaign LA's scope.
+
+**Acceptance:** Credits opens the ported retail credits screen and
+returns to character select; button re-enabled.
+
 ## #399 — Launcher: no test ever constructs MainWindow, so code-behind defects reach the user gate
 
 **Status:** DONE (this commit, Campaign LA UI-test slice) — closed via