Improve AI correction: loading indicator, field safety, memory, dismiss

- Show "…" placeholder immediately after debounce so users know the AI
  is working (KIND_AI_LOADING_FLAG = 0x20000)
- Skip AI correction in password, URL, and e-mail fields
  (mIsGeneralTextInput + mIsPasswordField guards in InputLogic)
- Protect suggestion strip from being cleared while AI suggestion is
  visible (mAiSuggestionVisible flag + clearAiSuggestionAndSetNeutral)
- Release Gemma 4 engine on TRIM_MEMORY_RUNNING_CRITICAL
- Long-press on AI suggestion dismisses it (dismissAiSuggestion)
- Warm-up model at IME startup for instant first correction

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/main/java/helium314/keyboard/latin/ai/AiCorrectionEngine.kt

@@ -9,7 +9,9 @@ import com.google.ai.edge.litertlm.ConversationConfig
 import com.google.ai.edge.litertlm.Engine
 import com.google.ai.edge.litertlm.EngineConfig
 import com.google.ai.edge.litertlm.SamplerConfig
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import java.io.File
 
@@ -114,6 +116,21 @@ class AiCorrectionEngine(private val context: Context) {
         }
     }
 
+    /**
+     * Pre-loads the model in the background so the first correction request
+     * doesn't have to wait. Call once after IME startup.
+     */
+    fun warmUp(scope: CoroutineScope) {
+        scope.launch(Dispatchers.IO) {
+            try {
+                getOrCreate()
+                Log.i(TAG, "Warm-up complete")
+            } catch (ex: Exception) {
+                Log.w(TAG, "Warm-up failed (model may not be present yet): ${ex.message}")
+            }
+        }
+    }
+
     fun close() {
         engine?.close()
         engine = null

app/src/main/java/helium314/keyboard/latin/ai/AiSuggestionManager.kt

@@ -45,6 +45,10 @@ class AiSuggestionManager {
         const val KIND_AI_FLAG = 0x10000
         const val KIND_AI_CORRECTION = SuggestedWordInfo.KIND_CORRECTION or KIND_AI_FLAG
 
+        /** Marks a transient "loading" placeholder — not tappable. */
+        const val KIND_AI_LOADING_FLAG = 0x20000
+        const val KIND_AI_LOADING = SuggestedWordInfo.KIND_CORRECTION or KIND_AI_LOADING_FLAG
+
         /**
          * Factory method accessible from Java (LatinIME.java patch).
          * Returns a [CoroutineScope] tied to a SupervisorJob so individual
@@ -126,6 +130,20 @@ class AiSuggestionManager {
     /** Returns the original (pre-correction) sentence, or null if none is pending. */
     fun getOriginalSentence(): String? = originalSentence
 
+    /** Shows a non-interactive "…" placeholder while inference is running. */
+    fun showLoadingPlaceholder() {
+        val wordInfo = SuggestedWordInfo(
+            "…", "", Int.MAX_VALUE, KIND_AI_LOADING,
+            null, SuggestedWordInfo.NOT_AN_INDEX, SuggestedWordInfo.NOT_A_CONFIDENCE
+        )
+        val words = SuggestedWords(
+            arrayListOf(wordInfo), null, wordInfo,
+            false, false, false,
+            SuggestedWords.INPUT_STYLE_PREDICTION, SuggestedWords.NOT_A_SEQUENCE_NUMBER
+        )
+        accessor?.showAiSuggestion(words)
+    }
+
     /**
      * Clears the AI suggestion from the strip.
      * Called when the correction matches the original (no change needed)
@@ -134,6 +152,6 @@ class AiSuggestionManager {
     fun clearSuggestion() {
         _currentSuggestion.value = null
         originalSentence = null
-        accessor?.setNeutralSuggestionStrip()
+        accessor?.clearAiSuggestionAndSetNeutral()
     }
 }

app/src/main/java/helium314/keyboard/latin/ai/AiTriggerHook.kt

@@ -63,6 +63,7 @@ class AiTriggerHook(
         debounceJob?.cancel()
         debounceJob = scope.launch {
             delay(DEBOUNCE_MS)
+            manager.showLoadingPlaceholder()
             Log.d(TAG, "Triggering AI correction for: \"$sentence\"")
             val corrected = engine.correctSentence(sentence)
             if (corrected != sentence) {