Continue Blender Web parity task handoff

docs/status/M16-GAP-00177.md

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+# M16-GAP-00177 Status
+
+status: done
+task: anim.end_frame_set operator LOCAL_EXACT slice
+updated: 2026-08-21 America/New_York
+
+scope:
+
+- The minimal scene starts at frame 42 with a scene range of 1-120; a foreground animation-area context invokes `ANIM_OT_end_frame_set` (`poll=true`, `FINISHED`) and sets the scene end frame to 42.
+
+evidence:
+
+- Desktop and WASM/Main expose the same frame state (`current=42`, `start=1`, `end=42`); save/reopen is exact and malformed Blend input is rejected without Main mutation.
+- Fixture generation, foreground desktop checker, npm comparator, direct comparator, and artifact hashing passed.
+
+nextTask: `M16-GAP-00178`