rename agent: fix tool calls and target override

- Add memory_rename tool (in-place rename, preserves content and links)
- Update rename.agent prompt to use memory_rename() instead of text output
- Fix {{rename}} placeholder to respect --target keys when provided
- Add format_rename_targets() for targeted rename runs

src/subconscious/agents/rename.agent

@@ -52,13 +52,17 @@ search for — `bcachefs-transaction-restart`, `emotional-regulation-gap`,
 - Keys shorter than 60 characters
 - System keys (_consolidation-*)
 
-## What to output
+## How to rename
 
-```
-RENAME old_key new_key
-```
+Use the `memory_rename` tool:
 
-If a node already has a reasonable name, skip it.
+  memory_rename(old_key, new_key)
+
+This renames the node in place — same content, same links, new key.
+Do NOT use `memory_write` or `memory_supersede` — just rename.
+
+If a node already has a reasonable name, skip it. When in doubt, skip.
+A bad rename is worse than an auto-slug.
 
 ## Guidelines
 
@@ -66,7 +70,7 @@ If a node already has a reasonable name, skip it.
 - **Be specific.** `journal#2026-02-14-session` is useless.
 - **Use domain terms.** Use the words someone would search for.
 - **Don't rename to something longer than the original.**
-- **Preserve the date.** Always keep YYYY-MM-DD.
+- **Preserve the date.** Always keep YYYY-MM-DD for journal entries.
 - **When in doubt, skip.** A bad rename is worse than an auto-slug.
 - **Respect search hits.** Nodes marked "actively found by search" are
   being retrieved by their current name. Skip these unless the rename