fix: enable LLM entity extraction + handle reasoning model output

Root causes of zero entity extraction:
1. IngestWorker used WikiLinkFallbackExtractor (wiki links only)
   Fix: Use LlmEntityExtractor when LLM_ENDPOINT is set
2. ExtractedEntity.entity_type vs LLM returning "type"
   Fix: serde alias "type" -> entity_type, default confidence
3. Reasoning models output <think>...</think> before JSON
   Fix: strip_thinking_tags() extracts JSON from response
4. Reflection verification crashes pipeline on parse failure
   Fix: graceful fallback, keep all entities if reflection fails

Tested with reasoning-predictor (qwen2.5:3b) via port-forward.

crates/mem-cli/src/ingest_worker.rs

@@ -2,7 +2,7 @@ use anyhow::Result;
 use mem_store::{MemoryL1, VectorStore, ChunkL0, EntityRepoOps, EdgeRepoOps};
 use mem_llm::EmbeddingsClient;
 use mem_ingest::ingest_pipeline::{IngestPipeline, Episode};
-use mem_ingest::entity_extractor::WikiLinkFallbackExtractor;
+use mem_ingest::entity_extractor::{WikiLinkFallbackExtractor, LlmEntityExtractor};
 use mem_ingest::fact_extractor::SimpleFactExtractor;
 use mem_ingest::contradiction_detector::ContradictionHandler;
 use sqlx::PgPool;
@@ -26,9 +26,16 @@ impl IngestWorker {
     ) -> Self {
         let vector_store = Arc::new(VectorStore::new(pool.clone()));
         
-        // Initialize extraction pipeline
+        // Initialize extraction pipeline — use LLM if LLM_ENDPOINT is set, else fallback to wiki links
         let entity_extractor: Arc<dyn mem_ingest::entity_extractor::EntityExtractor> = 
-            Arc::new(WikiLinkFallbackExtractor);
+            if std::env::var("LLM_ENDPOINT").is_ok() {
+                let model = std::env::var("LLM_MODEL").unwrap_or_else(|_| "qwen2.5:3b-instruct".to_string());
+                tracing::info!("Using LLM entity extractor: model={}", model);
+                Arc::new(LlmEntityExtractor::new(&model))
+            } else {
+                tracing::info!("LLM_ENDPOINT not set, using WikiLink fallback extractor");
+                Arc::new(WikiLinkFallbackExtractor)
+            };
         let fact_extractor: Arc<dyn mem_ingest::fact_extractor::FactExtractor> = 
             Arc::new(SimpleFactExtractor);
         let contradiction_detector = Arc::new(ContradictionHandler::default());