refactor(settings): implement Service annotation and refactor ZonedDateTimeConverter

Implement the Service annotation at the class level to ensure proper registration and management of the settings state service. Additionally, refactor the ZonedDateTimeConverter to be a top-level class for better organization and readability.

Author: phodal

src/main/kotlin/cc/unitmesh/devti/settings/AutoDevSettingsState.kt

@@ -2,6 +2,7 @@ package cc.unitmesh.devti.settings
 
 import com.intellij.openapi.application.ApplicationManager
 import com.intellij.openapi.components.PersistentStateComponent
+import com.intellij.openapi.components.Service
 import com.intellij.openapi.components.State
 import com.intellij.openapi.components.Storage
 import com.intellij.util.xmlb.Converter
@@ -10,6 +11,7 @@ import com.intellij.util.xmlb.annotations.OptionTag
 import java.time.ZonedDateTime
 import java.time.format.DateTimeFormatter
 
+@Service(Service.Level.APP)
 @State(name = "cc.unitmesh.devti.settings.DevtiSettingsState", storages = [Storage("DevtiSettings.xml")])
 class AutoDevSettingsState : PersistentStateComponent<AutoDevSettingsState> {
     var gitType = DEFAULT_GIT_TYPE
@@ -69,19 +71,16 @@ class AutoDevSettingsState : PersistentStateComponent<AutoDevSettingsState> {
         val maxTokenLength: Int get() = getInstance().fetchMaxTokenLength()
         val language: String get() = getInstance().fetchLocalLanguage()
 
-        var lastCheckTime: ZonedDateTime? = getInstance().lastCheck
-
         fun getInstance(): AutoDevSettingsState {
             return ApplicationManager.getApplication().getService(AutoDevSettingsState::class.java).state
         }
+    }
+}
 
-        class ZonedDateTimeConverter : Converter<ZonedDateTime>() {
-            override fun toString(value: ZonedDateTime): String? = value.format(DateTimeFormatter.ISO_ZONED_DATE_TIME)
+class ZonedDateTimeConverter : Converter<ZonedDateTime>() {
+    override fun toString(value: ZonedDateTime): String? = value.format(DateTimeFormatter.ISO_ZONED_DATE_TIME)
 
-            override fun fromString(value: String): ZonedDateTime? {
-                return ZonedDateTime.parse(value, DateTimeFormatter.ISO_ZONED_DATE_TIME)
-            }
-        }
+    override fun fromString(value: String): ZonedDateTime? {
+        return ZonedDateTime.parse(value, DateTimeFormatter.ISO_ZONED_DATE_TIME)
     }
-
 }