fix(#1079): revert meal planner to generateOnce, fix deadlock in generateStructuredOnce

.gitignore

@@ -54,3 +54,6 @@ third_party/sherpa-onnx/
 
 # Legacy local Sherpa voice assets (kept ignored if they still exist from old setup flows).
 core/voice/src/main/assets/sherpa-tts/
+
+# Agent plans (local-only)
+.omp/plans/

core/inference/src/main/java/com/kernel/ai/core/inference/LiteRtInferenceEngine.kt

@@ -966,7 +966,10 @@ class LiteRtInferenceEngine @Inject constructor(
         systemPrompt: String?,
         thinkingEnabled: Boolean?,
     ): String = withContext(LlmDispatcher) {
-        val config = currentConfig ?: return@withContext ""
+        val config = currentConfig ?: run {
+            Log.w(TAG, "generateStructuredOnce: currentConfig is null — engine not initialized?")
+            return@withContext ""
+        }
         Log.d(
             TAG,
             "generateStructuredOnce: spec='${spec.toolName}', schemaLen=${spec.jsonSchema.length}, thinking=$thinkingEnabled",
@@ -1024,7 +1027,10 @@ class LiteRtInferenceEngine @Inject constructor(
                     safeClose(conversation, "conversation")
                 }
 
-                val eng = engine ?: return@withContext ""
+                val eng = engine ?: run {
+                    Log.w(TAG, "generateStructuredOnce: engine is null — was it evicted?")
+                    return@withContext ""
+                }
                 val convConfig = buildConversationConfig(_activeBackend.value ?: BackendType.CPU, requestedConfig)
 
                 // Isolate to synthetic tool only — no other tools interfere with constrained decoding.
@@ -1184,13 +1190,15 @@ class LiteRtInferenceEngine @Inject constructor(
                     }
                 } finally {
                     resetExperimentalFlags()
-                    if (shouldSwapConfig) {
-                        resetConversationForConfig(config)
-                    }
                 }
             } finally {
                 generationMutex.unlock()
+                if (shouldSwapConfig) {
+                    resetConversationForConfig(config)
+                }
             }
+        } catch (ce: CancellationException) {
+            throw ce
         } catch (e: Exception) {
             Log.w(TAG, "generateStructuredOnce: error", e)
             ""