Let a behavior hear the end of an animation it played itself

A behavior that played an animation on the parent of its owner never
heard it finish. On animation finished listened to the owner and to
what stands below it, and the parent stands above.

- Play animation notes on the player which behavior asked for it.
- On animation finished hears, as before, every animation on the
  owner or below it, and now also every animation the behavior
  played itself, on whatever object. Its output object names that
  object.
- Two behaviors that both played the same animation on the same
  object each hear its end once.
- A behavior that is called by Run behavior or heard by an On node
  counts as the behavior it sits in.
- The description of the node and the engine prompt say so.

Tests:
- Gate on melektaus-atx: 218 files, 3392 tests, CHECK EXIT 0.
- Two new unit tests: the behavior hears the animation on the parent
  of its owner while a bystander does not, and two starters hear it
  once each.
- Both counter-probes bite.
- e2e 6,17-26 on melektaus-atx: 480 checks, all pass.
- No new e2e check, and nothing was looked at in the browser. The
  rule for called and heard behaviors has no test of its own.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

benchmark/engine-prompt.md

@@ -304,7 +304,7 @@ An animation asset is a timeline over one **root asset** (a sprite, text, contai
 - Numbers and colours blend between keys; textures, booleans, texts and choices hold until the next key. The playhead moves every tick, not only on whole frames. A row may be **relative**: its numbers are added to what the target held when the animation started.
 - Each key of a blending row has an **easing** to the next key: Linear, Step, the curves Sine, Quad, Cubic, Quart, Quint, Expo, Circ, Back, Elastic, Bounce each as In, Out or In-out, or a curve asset.
 - **Animation tab:** a header (root picker, *+ Row*, Play/Pause, Fit), a preview that shows the root at the playhead without changing the document, and a timeline with a frame ruler: double-click a cell to set a key, click or band-select keys, drag to move them, `Ctrl`+drag to duplicate, `Delete` removes them, copy and paste at the playhead, click the ruler to scrub. The selected key's value and easing are edited in the inspector.
-- **Runtime:** `Play animation` (object, animation, `blend` seconds to fade in from the current values, `blend out` for Once (reset), `restart`), `Stop animation` (with optional blend out), `Pause animation`. Playing an animation on a placed container plays it on that instance alone. Several animations may run on one object; where two write the same property the one started later wins, and a behavior writing it in the same frame wins over both. `On animation finished` fires exactly once in the frame a Once animation ends. `Animation playing` returns `playing`, `progress` (0 to 1) and `time left`; `Animation length` returns the seconds of one pass.
+- **Runtime:** `Play animation` (object, animation, `blend` seconds to fade in from the current values, `blend out` for Once (reset), `restart`), `Stop animation` (with optional blend out), `Pause animation`. Playing an animation on a placed container plays it on that instance alone. Several animations may run on one object; where two write the same property the one started later wins, and a behavior writing it in the same frame wins over both. `On animation finished` fires exactly once in the frame a Once animation ends. A behavior hears it for animations on its owner or below it, and for every animation it played itself on any object. `Animation playing` returns `playing`, `progress` (0 to 1) and `time left`; `Animation length` returns the seconds of one pass.
 - Animations run in play only; the scene view shows objects as stored.
 
 ## 16. Shaders