refactor: remove bottom navigation bar (#665 #666 #667 #668) (#672)

* refactor(nav): remove bottom NavigationBar from Scaffold (#665)

* refactor(theme): remove BottomNavDisplayMode enum (#666)

* refactor(settings): remove nav bar customization page (#667)

* chore: clean up unused imports after bottom nav removal (#668)

* chore: remove dead bottom nav infrastructure after removal

- Remove SettingsNavBar NavKey (NavigationKeys.kt)
- Remove bottomNavItems field from ServerStoreState + migration code
- Remove _bottomNavItemsFlow, getBottomNavItems, setBottomNavItems from AuthManager
- Remove bottomNavItems handling from selfHealed() (ServerCollectionOps)
- Remove redundant bottomBar={} from Scaffold (Navigation.kt)
- Remove unused nav bar strings from values/strings.xml + values-ko/strings.xml
- Remove content_desc_move_up/down/remove_item strings
- Update SettingsViewModelTest.kt (drop stale getBottomNavItems mock)
- Update ServerStoreTest.kt (remove bottomNavItems assertions)

---------

Co-authored-by: M57 <Hy4ri@users.noreply.github.com>

app/src/test/java/com/m57/hermescontrol/data/config/ServerStoreTest.kt

@@ -68,15 +68,6 @@ class ServerStoreTest {
             )
         val healed = state.selfHealed()
         assertNull(healed.selectedProfileId)
-
-        // Test empty bottomNavItems
-        val state2 =
-            ServerStoreState(
-                bottomNavItems = emptyList(),
-            )
-        val healed2 = state2.selfHealed()
-        assertEquals(5, healed2.bottomNavItems.size)
-        assertEquals("ChatScreen", healed2.bottomNavItems[0])
     }
 
     @Test