agents: surface search hit counts to guide keep/demote decisions

Nodes actively found by search now show "Search hits: N ← actively
found by search, prefer to keep" in both the node section (seen by
extractor, linker, etc.) and rename candidate listings.

Extractor and rename prompts updated to respect this signal — merge
into high-hit nodes rather than demoting them, skip renaming nodes
that are working well in search.

poc-memory/agents/extractor.agent

@@ -110,6 +110,9 @@ New node keys should be descriptive: `skills#bcachefs-assert-triage`,
   nodes. Make existing ones better rather than adding more.
 - **DEMOTE aggressively.** If a node's useful content is now captured
   in a better node, demote it. This is how the graph gets cleaner.
+- **Respect search hits.** Nodes marked "actively found by search" are
+  being retrieved in live queries. Prefer to keep these — merge *into*
+  them rather than demoting them.
 - **Don't force it.** If the neighborhood is already well-organized,
   say so. "This neighborhood is clean — no changes needed" is a
   valid output. Don't produce filler.

poc-memory/agents/rename.agent

@@ -51,5 +51,8 @@ If a node already has a reasonable name, skip it.
 - **Don't rename to something longer than the original.**
 - **Preserve the date.** Always keep YYYY-MM-DD.
 - **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
+  clearly preserves searchability.
 
 {{rename}}