observation agent rewrite, edit command, daemon fixes

- observation.agent: rewritten to navigate graph and prefer refining
  existing nodes over creating new ones. Identity-framed prompt,
  goals over rules.
- poc-memory edit: opens node in $EDITOR, writes back on save,
  no-op if unchanged
- daemon: remove extra_workers (jobkit tokio migration dropped it),
  remove sequential chaining of same-type agents (in-flight exclusion
  is sufficient)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

poc-memory/src/cli/node.rs

@@ -399,6 +399,60 @@ pub fn cmd_write(key: &[String]) -> Result<(), String> {
     Ok(())
 }
 
+pub fn cmd_edit(key: &[String]) -> Result<(), String> {
+    if key.is_empty() {
+        return Err("edit requires a key".into());
+    }
+    let raw_key = key.join(" ");
+    let store = store::Store::load()?;
+    let key = store.resolve_key(&raw_key).unwrap_or(raw_key.clone());
+
+    let content = store.nodes.get(&key)
+        .map(|n| n.content.clone())
+        .unwrap_or_default();
+
+    let tmp = std::env::temp_dir().join(format!("poc-memory-edit-{}.md", key.replace('/', "_")));
+    std::fs::write(&tmp, &content)
+        .map_err(|e| format!("write temp file: {}", e))?;
+
+    let editor = std::env::var("EDITOR").unwrap_or_else(|_| "vi".into());
+    let status = std::process::Command::new(&editor)
+        .arg(&tmp)
+        .status()
+        .map_err(|e| format!("spawn {}: {}", editor, e))?;
+
+    if !status.success() {
+        let _ = std::fs::remove_file(&tmp);
+        return Err(format!("{} exited with {}", editor, status));
+    }
+
+    let new_content = std::fs::read_to_string(&tmp)
+        .map_err(|e| format!("read temp file: {}", e))?;
+    let _ = std::fs::remove_file(&tmp);
+
+    if new_content == content {
+        println!("No change: '{}'", key);
+        return Ok(());
+    }
+
+    if new_content.trim().is_empty() {
+        return Err("Content is empty, aborting".into());
+    }
+
+    drop(store);
+    let mut store = store::Store::load()?;
+    let result = store.upsert(&key, &new_content)?;
+    match result {
+        "unchanged" => println!("No change: '{}'", key),
+        "updated" => println!("Updated '{}' (v{})", key, store.nodes[&key].version),
+        _ => println!("Created '{}'", key),
+    }
+    if result != "unchanged" {
+        store.save()?;
+    }
+    Ok(())
+}
+
 pub fn cmd_lookup_bump(keys: &[String]) -> Result<(), String> {
     if keys.is_empty() {
         return Err("lookup-bump requires at least one key".into());