Require local setup embedding profile selection

.env.example

@@ -6,13 +6,19 @@
 # Get one at: https://platform.openai.com/api-keys
 OPENAI_API_KEY=
 
-# AI profiles. Defaults keep RA-H on OpenAI plus sqlite-vec.
-LLM_PROFILE=openai
+# AI profiles are selected during setup because embedding dimensions shape
+# the sqlite-vec tables. Use one:
+#
+#   npm run setup:local -- --profile openai
+#   npm run setup:local -- --profile qwen-local
+#
+# OpenAI profile:
+# LLM_PROFILE=openai
 # LLM_MODEL=gpt-4o-mini
-EMBEDDING_PROFILE=openai
+# EMBEDDING_PROFILE=openai
 # EMBEDDING_MODEL=text-embedding-3-small
 # EMBEDDING_DIMENSIONS=1536
-VECTOR_BACKEND=sqlite-vec
+# VECTOR_BACKEND=sqlite-vec
 
 # Supported local profile: point RA-H at OpenAI-compatible local endpoints.
 # Example Ollama: