v0.30.1: building the map from memory costs a quarter

• Why. On the live hub the first estimate read 6,993 notes for about $24: the note filter matched any note with a
  URL, a port or the word "worker".
• Fewer, better notes. Once live discovery has run, a note is read only when it names something discovery found (an
  IP, a guest, a service, a tunnel hostname) or clearly talks about infrastructure (LXC, Proxmox, NAS, Cloudflare, a
  mount path, a deploy script): 2,991 notes on the same hub.
• Half price. With an Anthropic model the extraction goes through the Message Batches API, like the filing check.
  The same hub now estimates about $5.90.
• For agents: nothing changes.