chore: rimuove emoji da codice e output terminale

Sostituisce tutti i simboli grafici con testo:
- checkmark/cross -> OK / ERRORE: / AVVISO:
- icone tema GUI -> testo Chiaro / Scuro

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

rag/retrieve.py

@@ -134,7 +134,7 @@ def run_loop(collection: chromadb.Collection, top_k: int) -> None:
         try:
             chunks = retrieve(collection, query, top_k)
         except (urllib.error.URLError, OSError) as e:
-            print(f"❌ Errore embedding (Ollama raggiungibile?): {e}\n")
+            print(f"ERRORE embedding (Ollama raggiungibile?): {e}\n")
             continue
 
         print()
@@ -204,13 +204,13 @@ def main() -> int:
     print()
 
     if not CHROMA_DIR.exists():
-        print("❌ chroma_db/ non trovata — esegui prima ingestion", file=sys.stderr)
+        print("ERRORE: chroma_db/ non trovata — esegui prima ingestion", file=sys.stderr)
         return 1
 
     client = chromadb.PersistentClient(path=str(CHROMA_DIR))
     collections = [c.name for c in client.list_collections()]
     if collection_name not in collections:
-        print(f"❌ Collection '{collection_name}' non trovata in chroma_db/", file=sys.stderr)
+        print(f"ERRORE: Collection '{collection_name}' non trovata in chroma_db/", file=sys.stderr)
         if args.stem:
             print(f"   → python ingestion/ingest.py --stem {collection_name}", file=sys.stderr)
         else:
@@ -218,7 +218,7 @@ def main() -> int:
         return 1
 
     collection = client.get_collection(collection_name)
-    print(f"✅ Collection '{collection_name}' caricata ({collection.count()} chunk)\n")
+    print(f"OK Collection '{collection_name}' caricata ({collection.count()} chunk)\n")
 
     run_loop(collection, args.top_k)
     return 0