use config for identity node references

Replace hardcoded "identity" lookups with config.core_nodes so
experience mining and init work with whatever core nodes are
configured, not just a node named "identity".

Co-Authored-By: ProofOfConcept <poc@bcachefs.org>

src/enrich.rs

@@ -330,10 +330,12 @@ pub fn experience_mine(
     let conversation = format_conversation(&messages);
     println!("  {} messages, {} chars", messages.len(), conversation.len());
 
-    // Load identity
-    let identity = store.nodes.get("identity")
-        .map(|n| n.content.clone())
-        .unwrap_or_default();
+    // Load core identity nodes for context
+    let cfg = crate::config::get();
+    let identity: String = cfg.core_nodes.iter()
+        .filter_map(|k| store.nodes.get(k).map(|n| n.content.as_str()))
+        .collect::<Vec<_>>()
+        .join("\n\n");
 
     // Get recent episodic entries to avoid duplication
     let mut journal: Vec<_> = store.nodes.values()