fix(core): prevent empty input processing in SketchInputListener

Add check to ignore empty or blank user input in `manualSend` method to avoid unnecessary processing.

Author: phodal

core/src/main/kotlin/cc/unitmesh/devti/sketch/SketchInputListener.kt

@@ -57,6 +57,8 @@ open class SketchInputListener(
     open fun getInitPrompt(): String = systemPrompt
 
     override fun manualSend(userInput: String) {
+        if (userInput.trim().isEmpty() || userInput.trim().isBlank()) return
+
         ApplicationManager.getApplication().executeOnPooledThread {
             val devInProcessor = LanguageProcessor.devin()
             val compiledInput = runReadAction { devInProcessor?.compile(project, userInput) } ?: userInput