Show skeleton on actual Discover filter changes, not just first load

Changing type/catalog/genre didn't clear the previous results, so the
old (now-mismatched) results stayed visible for the entire fetch
duration instead of the skeleton grid — results only ever got replaced
once the new fetch completed. Only clear on a genuine filter change
(compare against the previous DiscoverFiltersUiModel) so a plain tab
revisit with unchanged filters still silently keeps showing cached
results while it revalidates in the background, per the earlier fix.

app/src/main/java/com/fluxa/app/ui/catalog/AndroidDiscoverDataSource.kt

@@ -55,7 +55,11 @@ class AndroidDiscoverDataSource(
     }
 
     override suspend fun updateFilters(filters: DiscoverFiltersUiModel) {
+        val filtersChanged = filters != this.filters.value
         this.filters.value = filters
+        if (filtersChanged) {
+            homeViewModel.clearDiscoverResults()
+        }
         homeViewModel.loadDiscoverCatalogFilters(filters.contentType, filters.catalogKey)
         homeViewModel.discover(
             type = filters.contentType,

app/src/main/java/com/fluxa/app/ui/catalog/HomeViewModel.kt

@@ -1002,6 +1002,10 @@ class HomeViewModel @Inject constructor(
         )
     }
 
+    fun clearDiscoverResults() {
+        _headlessDiscoverResults.value = emptyList()
+    }
+
     fun discover(type: String, catalogKey: String?, genre: String?, year: String?, rating: Float?, provider: String?, region: String?) {
         viewModelScope.launch {
             _headlessDiscoverLoading.value = true