feat(notification): support custom notification IDs

Update `NotificationSys.showNotification` to accept an optional `id`
parameter. This allows different notifications to be displayed
simultaneously by the system instead of overwriting each other.

In `SettingsFragment` and `PlayerFragment`, assign specific unique IDs
for test, share, and update notifications.

app/src/main/java/com/michatec/radio/NotificationSys.kt

@@ -27,7 +27,7 @@ object NotificationSys {
         }
     }
 
-    fun showNotification(context: Context, title: String, content: String, intent: Intent? = null) {
+    fun showNotification(context: Context, title: String, content: String, intent: Intent? = null, id: Int = NOTIFICATION_ID) {
         val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
         createNotificationChannel(context)
 
@@ -51,6 +51,6 @@ object NotificationSys {
             .setAutoCancel(true)
             .build()
 
-        notificationManager.notify(NOTIFICATION_ID, notification)
+        notificationManager.notify(id, notification)
     }
 }

app/src/main/java/com/michatec/radio/PlayerFragment.kt

@@ -885,7 +885,8 @@ class PlayerFragment : Fragment(),
                         requireContext(),
                         "${getString(R.string.app_name)} $latestVersion",
                         getString(R.string.snackbar_update_available),
-                        intent = updateIntent
+                        intent = updateIntent,
+                        id = 1001
                     )
                 }
             }

app/src/main/java/com/michatec/radio/SettingsFragment.kt

@@ -330,7 +330,8 @@ class SettingsFragment : PreferenceFragmentCompat(), YesNoDialog.YesNoDialogList
             NotificationSys.showNotification(
                 context,
                 getString(R.string.pref_test_notification_title),
-                getString(R.string.notification_test_content)
+                getString(R.string.notification_test_content),
+                id = 1003
             )
             return@setOnPreferenceClickListener true
         }
@@ -413,7 +414,8 @@ class SettingsFragment : PreferenceFragmentCompat(), YesNoDialog.YesNoDialogList
                 NotificationSys.showNotification(
                     context,
                     getString(R.string.pref_share_app_thank_title),
-                    getString(R.string.pref_share_app_thank_message)
+                    getString(R.string.pref_share_app_thank_message),
+                    id = 1002
                 )
             }
             return@setOnPreferenceClickListener true