`drawing_apply_iso_layers` recorded its standard in `_active_layer_set` on
the backend, and `_role_layer` reads it ahead of the PlanSpec to decide where
`dimension_auto` / `construction_xline` file their output. It was neither a
`_DocState` field nor cleared by `_reset_document_state`, so an iso13567
sheet next to a mech one pushed the mech drawing's dimensions onto
`M-DIMEN-T-N` (created on demand), silently — and `drawing_critique` could
not see it because the same stale set drove the critique. The attribute
predates the registry (v1.5 `drawing_new` did not reset it either), but the
per-document claim of Task 21 covered it and the measured attribute list
missed it.
- `_DocState.active_layer_set` + `_ActiveField("active_layer_set")` on
`EzdxfBackend`: the set follows the active entry, bidirectionally.
- `PremiumContract._reset_document_state` clears it (declared on the mixin
like `_plan_spec`), which fixes COM's `_ensure_document_state` switch and
`drawing_new` / `drawing_open` / `disconnect` on both engines.
- tests: `test_active_layer_set_is_per_document` (headless registry, the
reviewer's repro plus the reverse direction) and the COM activate test now
also asserts the set is cleared and `_role_layer('dim')` is back on DIM.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd
