General improvements (#316)

* Added support for right text alignment in epub reader

* Added tabs management to PDF navigation drawer

* Implemented unified selection menu placement logic

* Added reset functionality for toolbar customization

* Improved highlight filtering in epub pagination

* Migrated hardcoded UI strings to string resources

* Extracted desktop application logic from Main.kt into modular files

* Refactored Main.kt by extracting PDF and EPUB logic into specialized files

* Added Spanish language support

* Added system default option to app language selection

app/src/test/java/com/aryan/reader/epubreader/EpubReaderBridgeAndControlsTest.kt

@@ -198,4 +198,29 @@ class EpubReaderBridgeAndControlsTest {
         assertTrue(ReaderTool.entries.any { it.category == "Overflow Menu" })
         assertEquals("Top Bar", ReaderTool.SCREEN_ORIENTATION.category)
     }
+
+    @Test
+    fun `reader toolbar reset defaults match first-run toolbar defaults`() {
+        assertEquals(setOf(ReaderTool.SCREEN_ORIENTATION.name), defaultReaderHiddenTools())
+        assertEquals(ReaderTool.entries.toList(), defaultReaderToolOrder())
+        assertEquals(
+            ReaderTool.entries.filter { it.category == "Bottom Bar" }.map { it.name }.toSet(),
+            defaultReaderBottomTools()
+        )
+
+        val defaultItems = buildReaderToolbarItems(
+            hiddenTools = defaultReaderHiddenTools(),
+            toolOrder = defaultReaderToolOrder(),
+            bottomTools = defaultReaderBottomTools()
+        )
+
+        assertEquals(
+            ToolbarSection.HIDDEN,
+            defaultItems.single { it.tool == ReaderTool.SCREEN_ORIENTATION }.section
+        )
+        assertEquals(
+            ToolbarSection.BOTTOM,
+            defaultItems.single { it.tool == ReaderTool.SLIDER }.section
+        )
+    }
 }