Show download-complete snackbar with filename and Show action

Surfaces "Download complete for <filename>" with a Show action that
opens the Downloads screen, matching the design. The ViewModel already
emits the filename via ShowDownloadComplete — only the Fragment copy
and string format needed updating.

Also removes a duplicate setPinned override accidentally added to
RecordingRenameRepository, which was breaking compileDebugUnitTestKotlin.

Author: GerardPaligot

duckchat/duckchat-impl/src/main/java/com/duckduckgo/duckchat/impl/history/ChatHistoryFragment.kt

@@ -140,7 +140,7 @@ class ChatHistoryFragment : DuckDuckGoFragment(R.layout.fragment_chat_history) {
     private fun onNavigationEvent(event: ChatHistoryViewModel.NavigationEvent) {
         when (event) {
             is ChatHistoryViewModel.NavigationEvent.OpenRename -> openRenameScreen(event.chatId, event.currentTitle)
-            is ChatHistoryViewModel.NavigationEvent.ShowDownloadComplete -> showDownloadCompleteSnackbar()
+            is ChatHistoryViewModel.NavigationEvent.ShowDownloadComplete -> showDownloadCompleteSnackbar(event.fileName)
             ChatHistoryViewModel.NavigationEvent.ShowExportError ->
                 Snackbar.make(binding.root, R.string.duck_ai_chat_history_download_error, Snackbar.LENGTH_SHORT).show()
         }
@@ -165,8 +165,9 @@ class ChatHistoryFragment : DuckDuckGoFragment(R.layout.fragment_chat_history) {
             .show()
     }
 
-    private fun showDownloadCompleteSnackbar() {
-        Snackbar.make(binding.root, R.string.duck_ai_chat_history_download_complete, Snackbar.LENGTH_LONG)
+    private fun showDownloadCompleteSnackbar(fileName: String) {
+        val message = getString(R.string.duck_ai_chat_history_download_complete, fileName)
+        Snackbar.make(binding.root, message, Snackbar.LENGTH_LONG)
             .setAction(R.string.duck_ai_chat_history_download_view) {
                 globalActivityStarter.start(requireContext(), DownloadsScreens.DownloadsScreenNoParams)
             }

duckchat/duckchat-impl/src/main/res/values/donottranslate.xml

@@ -110,7 +110,7 @@
     <string name="duck_ai_chat_history_pin_snackbar">Chat pinned</string>
     <string name="duck_ai_chat_history_unpin_snackbar">Chat unpinned</string>
     <string name="duck_ai_chat_history_undo">Undo</string>
-    <string name="duck_ai_chat_history_download_complete">Saved chat to Downloads</string>
-    <string name="duck_ai_chat_history_download_view">View</string>
+    <string name="duck_ai_chat_history_download_complete">Download complete for %1$s</string>
+    <string name="duck_ai_chat_history_download_view">Show</string>
     <string name="duck_ai_chat_history_download_error">Couldn\'t export chat</string>
 </resources>

duckchat/duckchat-impl/src/test/kotlin/com/duckduckgo/duckchat/impl/history/RenameChatViewModelTest.kt

@@ -74,6 +74,4 @@ private class RecordingRenameRepository : ChatHistoryRepository {
         errorToThrow?.let { throw it }
         renames += chatId to newTitle
     }
-
-    override suspend fun setPinned(chatId: String, pinned: Boolean) = Unit
 }