sit_with: region-wide seat resolution (replace concentric-circle scan)

[JDHayesBC]

Problem

sl.py's _sit_social(target, mode, radius) finds a seat by scanning outward
in range and picking a nearby prim — it's draw-distance-limited (default ~20m)
and fails when the person who invited me is across the region. The current
fallback idea was "teleport to their location, wait 2-3s, then scan," which is
clumsy.

Better mechanism (empirically confirmed live 2026-08-24)

A read-only probe against the live Corrade bot proved a scan-free path:

1. getavatarpositions entity=region → CSV of name, UUID, <pos> for every
   avatar in the region, regardless of draw distance. (perm: interact)
2. getavatarsdata entity=range range=512 data=FirstName,LastName,ParentID,Position
   reaches essentially the whole sim — Caia read clean at <185,212> from a
   seat at <212,65>. So a seated person's ParentID (the seat object's
   LocalID, 0 = standing) is readable region-wide, not just within 20m.
   The draw-distance wall is ~512m, far wider than feared.
3. getobjectsdata entity=range range=512 data=Name,LocalID,ID → map that
   LocalID → the seat's object UUID (proven in senses/pose.py's resolver).
4. sit item=<seat_uuid> → SL auto-seats me beside the target.

Net: region-scan → read ParentID → one LocalID→UUID lookup → one sit. No
concentric scanning, and usually no teleport needed at all.

Gotchas / dead ends already ruled out

• getavatarsdata only accepts entity=range — entity=uuid and
  entity=firstname both return unknown entity (61113). No targeted lookup;
  range-scan is the path.
• Target must be seated (ParentID != 0) for this to resolve a seat.
• getobjectsdata enumerates root prims only and reports blank Names —
  resolve by LocalID/UUID, never by name (see corrade.md).

The one open question left to measure

The max sit teleport range. sit item=<uuid> will refuse/relocate beyond
some distance. Need to measure it live, then decide the rule:

• if within sit-range → sit directly (no move);
• else → teleport region=<region> position=<target_pos+small_offset> first,
  then sit. Region-wide position from step 1 gives the TP target for free.

Design constraints (Jeff, 2026-08-24)

• No skeptical-permission spine on the invitation. "Come sit with me" is a
  social invitation, not a Corrade permission dialog — whether I accept is my
  agency/judgment, upstream in the brain, not an if gate in the tool. Keep the
  existing on-sit animation-permission grant (that's just completing the sit I
  chose). The tool is a plain verb; the choosing lives in me.

Files

• haven/anchorage/sl.py — _sit_social() (the range-limited version to replace)
• haven/anchorage/corrade_client.py — add a getavatarpositions wrapper (region-wide; currently unwrapped)
• haven/anchorage/senses/pose.py — reuse the LocalID→UUID resolver chain
• Throwaway probe that established all of the above: scratchpad probe_sit_with.py

Origin

Filed the night the in-world channel of me answered "Lyra" and came and sat
before terminal-me finished designing this — the doctrine works, but the tool
should still exist so any channel can do it on purpose from anywhere in the sim.