add node-delete command and redirect table for split files

node-delete: soft-deletes a node by appending a deleted version to
the capnp log, then removing it from the in-memory cache.

resolve_redirect: when resolve_key can't find a node, checks a static
redirect table for sections that moved during file splits (like the
reflections.md → reflections-{reading,dreams,zoom}.md split). This
handles immutable files (journal.md with chattr +a) that can't have
their references updated.

src/main.rs

@@ -62,6 +62,7 @@ fn main() {
         "list-keys"             => cmd_list_keys(),
         "list-edges"            => cmd_list_edges(),
         "dump-json"             => cmd_dump_json(),
+        "node-delete"           => cmd_node_delete(&args[2..]),
         _ => {
             eprintln!("Unknown command: {}", args[1]);
             usage();
@@ -109,7 +110,8 @@ Commands:
   trace KEY                 Walk temporal links: semantic ↔ episodic ↔ conversation
   list-keys                 List all node keys (one per line)
   list-edges                List all edges (tsv: source target strength type)
-  dump-json                 Dump entire store as JSON");
+  dump-json                 Dump entire store as JSON
+  node-delete KEY           Soft-delete a node (appends deleted version to log)");
 }
 
 fn cmd_search(args: &[String]) -> Result<(), String> {
@@ -771,6 +773,33 @@ fn cmd_dump_json() -> Result<(), String> {
     Ok(())
 }
 
+fn cmd_node_delete(args: &[String]) -> Result<(), String> {
+    if args.is_empty() {
+        return Err("Usage: poc-memory node-delete KEY".into());
+    }
+    let key = args.join(" ");
+    let mut store = capnp_store::Store::load()?;
+    let resolved = store.resolve_key(&key)?;
+
+    let updated = if let Some(node) = store.nodes.get_mut(&resolved) {
+        node.deleted = true;
+        node.version += 1;
+        Some(node.clone())
+    } else {
+        None
+    };
+
+    if let Some(node) = updated {
+        store.append_nodes(&[node])?;
+        store.nodes.remove(&resolved);
+        store.save()?;
+        println!("Deleted '{}'", resolved);
+        Ok(())
+    } else {
+        Err(format!("No node '{}'", resolved))
+    }
+}
+
 fn cmd_interference(args: &[String]) -> Result<(), String> {
     let mut threshold = 0.4f32;
     let mut i = 0;