chore: code quality sweep 2026-05-04 / 2026-05-05

General code-quality and robustness pass across the plugin: thread-
safety on IPC state, resource-disposal cleanups, input validation,
defensive null-checks and a few small UX glitches. Compliance docs
(THIRD_PARTY_NOTICES, PRIVACY, COPYRIGHT) refreshed to v1.0.3.

Highlights
- ExtraChat IPC state synchronised across threads
- ChatLogWindow autocomplete no longer leaks the unmanaged
  ImGuiListClipper allocation
- ChatLogWindow + Popout style stack stays balanced when config
  toggles mid-frame
- Retention sweep and privacy cleanup wait for the actual filter
  pass instead of the fire-and-forget Task that started it
- Configuration.LatestVersion bumped to 13 to match the active
  migration path
- GameFunctions placeholder buffer guarded against oversized
  replacement names
- TellTarget.IsSet, ResolveTempInputChannel, InputPreview, IconUtil,
  Lender, Payloads, ExtraPayload all hardened against null / empty /
  EOF / cycle inputs
- FontManager Lodestone download stays in scope for a follow-up
  (timeout + lazy init pending)
- AutoTranslate replaced the msvcrt.dll memcmp P/Invoke with a
  managed Span comparison
- Privacy cleanup worker thread marked IsBackground = true
- Database cleanup now removes both legacy files in one click
- Tell-target name redacted in the verbose debug log

Compliance
- THIRD_PARTY_NOTICES: last-reviewed bumped to v1.0.3, Pidgin 3.5.1,
  SQLitePCLRaw.lib.e_sqlite3 3.50.3 listed as direct dependency with
  CVE-2025-6965 / CVE-2025-7709 rationale
- PRIVACY: last-reviewed bumped to v1.0.3, BetterTTV trigger wording
  clarified (list fetch at startup vs. on-demand image fetch)
- COPYRIGHT: upstream attribution range widened

Build: 0 warnings, 0 errors. No behavioural changes that would alter
existing user configuration or stored chat history.

HellionChat/Util/AutoTranslate.cs

@@ -1,6 +1,5 @@
 using System.Diagnostics;
 using System.Globalization;
-using System.Runtime.InteropServices;
 using System.Text;
 using Dalamud.Game;
 using Dalamud.Utility;
@@ -233,9 +232,6 @@ internal static class AutoTranslate
             .ToList();
     }
 
-    [DllImport("msvcrt.dll", CallingConvention = CallingConvention.Cdecl)]
-    private static extern int memcmp(byte[] b1, byte[] b2, nuint count);
-
     internal static void ReplaceWithPayload(ref byte[] bytes)
     {
         var search = "<at:"u8.ToArray();
@@ -279,7 +275,10 @@ internal static class AutoTranslate
                 start = -1;
             }
 
-            if (i + search.Length < bytes.Length && memcmp(bytes[i..], search, (nuint) search.Length) == 0)
+            // Pure managed comparison via Span avoids the msvcrt.dll P/Invoke,
+            // which is fragile under Wine and triggered an extra managed-to-
+            // unmanaged copy per check.
+            if (i + search.Length < bytes.Length && bytes.AsSpan(i, search.Length).SequenceEqual(search))
                 start = i;
         }
     }