naming agent: resolve node names before creation

Any time an agent creates a new node (WRITE_NODE) or the fact miner
stores extracted facts, a naming sub-agent now checks for conflicts
and ensures the key is meaningful:

- find_conflicts() searches existing nodes via component matching
- Haiku LLM decides: CREATE (good name), RENAME (better name),
  or MERGE_INTO (fold into existing node)
- WriteNode actions may be converted to Refine on MERGE_INTO

Also updates the rename agent to handle _facts-<UUID> nodes —
these are no longer skipped, and the prompt explains how to name
them based on their domain/claim content.

poc-memory/src/agents/prompts.rs

@@ -266,6 +266,7 @@ pub fn format_pairs_section(
 pub fn format_rename_candidates(store: &Store, count: usize) -> (Vec<String>, String) {
     let mut candidates: Vec<(&str, &crate::store::Node)> = store.nodes.iter()
         .filter(|(key, _)| {
+            if key.starts_with("_facts-") { return true; }
             if key.len() < 60 { return false; }
             if key.starts_with("journal#j-") { return true; }
             if key.starts_with("_mined-transcripts#f-") { return true; }
@@ -282,8 +283,9 @@ pub fn format_rename_candidates(store: &Store, count: usize) -> (Vec<String>, St
     let mut out = String::new();
     out.push_str(&format!("## Nodes to rename ({} of {} candidates)\n\n",
         candidates.len(),
-        store.nodes.keys().filter(|k| k.len() >= 60 &&
-            (k.starts_with("journal#j-") || k.starts_with("_mined-transcripts#f-"))).count()));
+        store.nodes.keys().filter(|k| k.starts_with("_facts-") ||
+            (k.len() >= 60 &&
+             (k.starts_with("journal#j-") || k.starts_with("_mined-transcripts#f-")))).count()));
 
     for (key, node) in &candidates {
         out.push_str(&format!("### {}\n", key));