Animate player display inactive transitions and death state

Player display now tracks displayParticipants separately from raw encounter
participants so active->inactive can animate out before removal, and inactive->
active can animate in. This preserves 1-list order, keeps DM display behavior
unchanged, and avoids fading dying/stable participants.

PlayerParticipantCard handles transitions:
- active->inactive: scale/slide/fade out, then parent removes from display list
- inactive->active: scale/slide/fade in
- alive->dead: keep visible with dim/desaturate/red-rim death cue + skull pulse
- dying/stable: full visible, no fade/removal

DisplayView inactive characterization updated to wait for exit animation before
asserting removal. TODO item removed.

src/tests/DisplayView.characterization.test.js

@@ -94,7 +94,7 @@ describe('DisplayView characterization', () => {
     expect(screen.getAllByText(/Dead/i).length).toBeGreaterThan(0);
   });
 
-  test('DisplayView hides inactive participants for all types', async () => {
+  test('DisplayView hides inactive participants for all types after fade-out', async () => {
     seedActiveDisplay([
       { ...participant('conscious'), id: 'active-pc', name: 'Active PC', isActive: true },
       { ...participant('conscious'), id: 'inactive-pc', name: 'Inactive PC', isActive: false },
@@ -103,7 +103,8 @@ describe('DisplayView characterization', () => {
     render(<App />);
 
     await waitFor(() => expect(screen.getByText('Active PC')).toBeInTheDocument());
-    expect(screen.queryByText('Inactive PC')).not.toBeInTheDocument();
+    // inactive held during exit animation, removed after transition
+    await waitFor(() => expect(screen.queryByText('Inactive PC')).not.toBeInTheDocument(), { timeout: 1500 });
     expect(screen.queryByText('Inactive Monster')).not.toBeInTheDocument();
   });
 });