docs(memory): add naming and maintenance guidance

AGENTS.md

@@ -34,6 +34,7 @@ You wake up fresh each session. These files are your continuity:
 - **Daily notes:** `memory/YYYY-MM-DD.md` (create `memory/` if needed) — raw logs of what happened
 - **Long-term:** `MEMORY.md` — your curated memories, like a human's long-term memory
 - **Named notes:** reserve separate memory files for long-lived plans, references, or investigations that truly need their own home; otherwise prefer folding notes back into the daily file
+- **When a named note is justified:** create one when the topic will likely span multiple sessions, accumulate evidence over time, or be reused as a reference. If it was just one conversation or one fix, prefer the daily note.
 - **Top-level `memory/` rule:** keep top-level mostly for daily notes. Put topical files in subfolders like `memory/ops/`, `memory/incidents/`, `memory/plans/`, `memory/references/`, or `memory/archive/`.
 
 Capture what matters. Decisions, context, things to remember. Skip the secrets unless asked to keep them.
@@ -287,6 +288,12 @@ You are free to edit `HEARTBEAT.md` with a short checklist or reminders. Keep it
 
 ### 🔄 Memory Maintenance (During Heartbeats)
 
+Light weekly checklist:
+- skim the last few daily notes
+- promote any durable truths into `MEMORY.md`
+- move obvious topical notes into `ops/`, `incidents/`, `plans/`, or `references/`
+- archive low-value clutter if top-level `memory/` is getting noisy
+
 Periodically (every few days), use a heartbeat to:
 
 1. Read through recent `memory/YYYY-MM-DD.md` files