fix #490 (part 2): plugin panels adopt an authored size change instead of keeping a stale saved size forever

MountPlugins registered every plugin window with authoredGeometryRevision
hard-coded to 0 (RetailUiRuntime.cs), so RetailWindowLayoutPersistence's
MigrateAuthoredGeometry -- gated on "saved revision >= authored revision"
-- never migrated a plugin window's saved size: 0 >= 0 forever. MossTank's
panel went 856x236 -> 984x271 and every user with a stored layout stayed
stuck at 856x236 with no way to see the new default.

Two changes:

1. MountPlugins now passes RetailWindowManager.ComputeAuthoredGeometryRevision
   (added previous commit) as the plugin window's authoredGeometryRevision,
   derived from the panel's own authored width/height/minw/minh/resizable.

2. MigrateAuthoredGeometry now compares revisions for INEQUALITY
   (saved.Revision == authored.Revision) instead of ordering
   (saved.Revision >= authored.Revision). A hash is not an incrementing
   counter -- two different authored sizes can hash in either order -- so
   "the authored size changed" has to mean "the value differs", not "the
   value went up". Built-in windows' hand-picked incrementing literals
   (chat: authoredGeometryRevision = 1) are unaffected: no existing saved
   revision is ever equal to a later, different literal either way.

Mutation shown to fail first: the two new PluginMarkupPanel_AuthoredSizeChanged_*
tests in RetailWindowLayoutPersistenceTests.cs reproduce the exact bug with
concrete literals (856x236/400/150/true -> 984x271/... and
200x100/100/80/true -> 220x110/...) chosen so ComputeAuthoredGeometryRevision's
OLD hash is >= the NEW hash for each pair -- confirmed via a throwaway probe
before writing the assertions, so the pre-fix run fails deterministically
rather than by chance of hash ordering. Both failed before this commit
(size stayed at the old authored extent) and pass after
(PluginMarkupPanel_AuthoredSizeUnchanged_KeepsUserResizedSize, unaffected
either way, is a regression-safety companion). Full RetailWindow/Markup/
PluginSidePanel filter: 249 passed (was 246), 0 failed, 0 skipped.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/AcDream.App/UI/RetailUiRuntime.cs

@@ -4767,11 +4767,20 @@ public sealed class RetailUiRuntime : IDisposable
                 // later registration/sidepanel failure then rolls the mounted
                 // subtree back through FailMount instead of leaking it.
                 _bindings.Plugins.CompleteMount(panel, Host.Root, element);
+                // #490 part 2: derive the authored-geometry revision from
+                // the panel's own authored extent instead of a hard-coded 0
+                // — see RetailWindowLayoutPersistence's class doc and
+                // RetailWindowManager.ComputeAuthoredGeometryRevision's own
+                // doc for why a plugin window can't use the built-in
+                // windows' manual-literal scheme.
+                int authoredGeometryRevision = RetailWindowManager.ComputeAuthoredGeometryRevision(
+                    element.Width, element.Height, element.MinWidth, element.MinHeight, element.Resizable);
                 RetailWindowHandle handle = Host.WindowManager.Register(
                     panel.WindowName,
                     element,
                     element,
-                    visibility);
+                    visibility,
+                    authoredGeometryRevision: authoredGeometryRevision);
                 _bindings.Plugins.CompleteWindowMount(
                     panel,
                     () => Host.WindowManager.Unregister(panel.WindowName));

src/AcDream.App/UI/RetailWindowLayoutPersistence.cs

@@ -9,6 +9,31 @@ namespace AcDream.App.UI;
 /// per-resolution settings. It deliberately ignores the temporary pre-login
 /// <c>default</c> character key so startup layout cannot overwrite a real
 /// character's state.
+///
+/// <para>
+/// <b>Authored-geometry revision (#490 part 2).</b> Every registered window
+/// carries an <c>authoredGeometryRevision</c> (see
+/// <see cref="RetailWindowHandle.AuthoredGeometryRevision"/>); a restore
+/// whose saved revision differs from the handle's current one replaces only
+/// the saved WIDTH/HEIGHT with the current authored size
+/// (<see cref="MigrateAuthoredGeometry"/>) — position, visibility, and
+/// collapsed/maximized state are untouched, and the clamp in
+/// <see cref="Apply"/> still re-fits the kept position to the live screen.
+/// Built-in retail-imported windows hand-pick that revision as a small
+/// incrementing literal at their <c>Register</c> call site (chat windows:
+/// <c>authoredGeometryRevision = 1</c>) — a deliberate author decision each
+/// time their authored size changes. Plugin windows have no such call site
+/// an author remembers to touch, so <c>MountPlugins</c> instead derives the
+/// revision automatically from the authored geometry tuple itself via
+/// <see cref="RetailWindowManager.ComputeAuthoredGeometryRevision"/>
+/// (width, height, min width, min height, resizable): unchanged authored
+/// geometry hashes to the same revision (a user's own resize survives
+/// restore), and ANY authored geometry change hashes to a different one
+/// (the stored size resets to the new default exactly once). Because a hash
+/// is not an ordered counter, the comparison is for INEQUALITY — see
+/// <see cref="MigrateAuthoredGeometry"/>'s own doc for why the original
+/// "newer revision only" read was wrong for this case.
+/// </para>
 /// </summary>
 public sealed class RetailWindowLayoutPersistence : IDisposable
 {
@@ -295,11 +320,26 @@ public sealed class RetailWindowLayoutPersistence : IDisposable
             handle.AuthoredGeometryRevision);
     }
 
+    /// <summary>
+    /// #490 part 2: compares revisions for INEQUALITY, not ordering. Built-in
+    /// retail-imported windows hand-pick a small incrementing literal
+    /// (0, 1, 2…) that only ever grows, so the original "migrate only if
+    /// saved &lt; authored" read fine for them. Plugin windows instead derive
+    /// their revision from a hash of the authored geometry itself
+    /// (<see cref="RetailWindowManager.ComputeAuthoredGeometryRevision"/>) so
+    /// their author never has to remember to bump a literal — but a hash is
+    /// not a counter, and two different authored sizes can hash in either
+    /// order. "The authored size changed" therefore means "the value
+    /// differs", not "the value went up"; treating it as ordered silently
+    /// dropped every size-decreasing (by hash value, not by pixels) plugin
+    /// update, which is exactly how MossTank's 856x236 -&gt; 984x271 bump got
+    /// stuck at the old size for every user with a stored layout.
+    /// </summary>
     private static UiWindowLayout MigrateAuthoredGeometry(
         UiWindowLayout saved,
         UiWindowLayout authored)
     {
-        if (saved.AuthoredGeometryRevision >= authored.AuthoredGeometryRevision)
+        if (saved.AuthoredGeometryRevision == authored.AuthoredGeometryRevision)
             return saved;
 
         return saved with