Add NPC theater poses: sit, photo, film, perform

Once an NPC reaches its intent waypoint it now does something instead of standing
in an idle T-pose:

- sit: the rig settles 0.34 m into a seat and the legs swing forward on the steps
- photo/film: influencers and tourists raise their camera prop briefly (a sine
  pulse, so it reads as taking a shot rather than a permanently raised arm)
- perform: performers sway the sign board they carry

Pose selection lives in NpcAvatar.theater_pose() (intent + arrived); the math is in
pure helpers (crouch_for_pose, prop_lift_for_pose, sway_for_pose) so it is
headless-testable. Prop/leg nodes are captured at build time and animated from
their rest offsets. Performers also get a hand-held board and post.

Tests/docs
- Headless suite 120 -> 127 (test_npc_theater.gd).
- Verified visually with a staged sit/photo/perform lineup in front of the entrance.
- README, TODO section moved to DONE, MEMORY. Version 0.2.7.

MEMORY.md

@@ -21,7 +21,8 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
   Windowed control smoke: `godot --path . --script res://src/test/smoke_focus_radial.gd` → exit 0.
 - `main` is in sync with origin. **v0.2.2** tags the session-shell + world-follow-up commit;
   CI builds the portable binaries, NSIS installer, and AppImage on the tag push.
-- Next work: `TODO.md` NPC theater poses (sit/photo/perform), then audio and accessibility.
+- Next work: `TODO.md` audio (crowd bed rising with mood, radio crackle), then accessibility and
+  scenario content.
 - Do not re-open `override_access`. Do not bind wand to `W`. Do not remove the radio easter egg.
 
 ## Current State
@@ -94,6 +95,12 @@ Session memory for durable decisions, state, and gotchas. Keep concise, remove o
   `_begin_incident()` now starts one per focused NPC (`has_open_incident()` guard), verbs call
   `_ensure_incident()`, and `ShiftCoordinator._finish_shift()` closes leftovers as `unresolved`
   before building the review.
+- **NPC theater (2026-10-31):** `NpcAvatar.theater_pose()` maps `intent` + `arrived` to
+  idle/sit/photo/film/perform. Pure helpers `crouch_for_pose`, `prop_lift_for_pose`,
+  `sway_for_pose` keep the math testable. Sit lowers the rig by 0.34 and swings the legs forward
+  (negative X pitch; positive looked like kneeling). `_photo_prop` is set for influencer/tourist
+  cameras, `_sign_prop` for protester/performer boards; their base Y values are captured at build
+  time so the animation offsets from rest.
 - **Body-camera timeline (2026-10-31):** `src/game/ui/event_timeline.gd` flattens
   `review.incidents.incidents[].events` into one time-ordered list (`flatten`), formats each row
   with `describe`, and steps with Left/Right or the buttons. `ShiftCoordinator.started_at_ms`