Complete the debug screen migration to Compose with Nav3

- Completed the UI and logic for pending items of Debug screen using Jetpack Compose.
- Implemented a new navigation system for settings using the navigation3
  lib as it is now stable.
- Reuses the `ScaffoldWithToolbar` composable and removed the previous
  `Toolbar` composable to avoid redundancy in code.
- Refactored the `SettingsViewModel` to use a `BooleanPreference` helper
  class to reuse and reducing boilerplate for state management.
- Created a shared `TextBase` composable to remove duplicated UI logic
  between `SwitchPreference` and `TextPreference`.
- Move the build-variant-dependent logic for LeakCanary and reused it in
  Compose and Fragment, this logic is used for ensuring the leak canary
  fields are only enabled in debug variants.
- Fixed a layout bug in `SwitchPreference` where long summary text could
  misalign the switch component and also adjusted the paddings for consistency.

app/src/debug/java/org/schabi/newpipe/settings/DebugSettingsBVDLeakCanary.java

@@ -1,20 +0,0 @@
-package org.schabi.newpipe.settings;
-
-import android.content.Intent;
-
-import leakcanary.LeakCanary;
-
-/**
- * Build variant dependent (BVD) leak canary API implementation for the debug settings fragment.
- * This class is loaded via reflection by
- * {@link DebugSettingsFragment.DebugSettingsBVDLeakCanaryAPI}.
- */
-@SuppressWarnings("unused") // Class is used but loaded via reflection
-public class DebugSettingsBVDLeakCanary
-        implements DebugSettingsFragment.DebugSettingsBVDLeakCanaryAPI {
-
-    @Override
-    public Intent getNewLeakDisplayActivityIntent() {
-        return LeakCanary.INSTANCE.newLeakDisplayActivityIntent();
-    }
-}

app/src/debug/java/org/schabi/newpipe/settings/DebugSettingsBVDLeakCanary.kt

@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: 2025-2026 NewPipe e.V. <https://newpipe-ev.de>
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package org.schabi.newpipe.settings
+
+import android.content.Intent
+import leakcanary.LeakCanary.newLeakDisplayActivityIntent
+
+/**
+ * Build variant dependent (BVD) leak canary API implementation for the debug settings fragment.
+ * This class is loaded via reflection by
+ * [DebugSettingsBVDLeakCanaryAPI].
+ */
+@Suppress("unused") // Class is used but loaded via reflection
+class DebugSettingsBVDLeakCanary :
+
+    DebugSettingsBVDLeakCanaryAPI {
+    override fun getNewLeakDisplayActivityIntent(): Intent {
+        return newLeakDisplayActivityIntent()
+    }
+}