Map Leader in the Python host model; record acadrust W blockers

Adds Leader validation and annotation/dimension-style reference checks to
ocs_plugin_api, maps 15 writable and 5 read-only fields in the adapter, and
adds staged_python_leader_lifecycle_over_real_ipc covering C/R/E/D/U/I/V/P.
The W gate stays open: acadrust's DXF writer omits the annotation handle and
DXF reads drop annotation_offset; DWG R2010+ does not store text size or the
hookline flag. Each gap is pinned by a canary assertion.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/plugin-host-model-coverage-ledger.md

@@ -1,6 +1,6 @@
 # OCS canvas kind coverage ledger
 
-Use with [the completion plan](plugin-host-model-completion-plan.md). This ledger is current as of 20 September 2026: **22 of 43 canvas kinds have explicit geometry writes** (21 creatable, plus update-only `Insert`), **4 kinds are complete**, and 21 remain layer-only. `Mapped` means at least one non-layer field is exposed for Python writes; it does **not** mean the kind passes the completion gate. `Update-only` means Python creation is unavailable. `Layer-only` means raw inspection and canvas layer edits exist, but geometry is not mapped. Record actual evidence or a blocking issue before changing any status to `Complete`.
+Use with [the completion plan](plugin-host-model-completion-plan.md). This ledger is current as of 20 September 2026: **23 of 43 canvas kinds have explicit geometry writes** (22 creatable, plus update-only `Insert`), **4 kinds are complete**, and 20 remain layer-only. `Mapped` means at least one non-layer field is exposed for Python writes; it does **not** mean the kind passes the completion gate. `Update-only` means Python creation is unavailable. `Layer-only` means raw inspection and canvas layer edits exist, but geometry is not mapped. Record actual evidence or a blocking issue before changing any status to `Complete`.
 
 Completion gate codes: **C** = create through Python document model; **R** = read; **E** = edit defining geometry and another property; **D** = delete; **U** = undo/redo and atomic failure; **I** = real IPC plus GUI/canvas pick or observable behavior; **W** = DWG and DXF save/reopen; **V** = invalid-input checks and untouched-field/reference preservation; **P** = build and load the in-tree bundled plugin with a manifest matching the host toolchain and acadrust source. A kind is `Complete` only when **C/R/E/D/U/I/W/V/P** all pass and its property catalog matches implementation. `Blocked` requires a specific dependency or failing fixture.
 
@@ -28,7 +28,7 @@ Completion gate codes: **C** = create through Python document model; **R** = rea
 | AttributeDefinition | **Integration-tested / DXF blocker pending revalidation** | Host commit `5b854bd1` maps block ownership plus every stable ATTDEF field except the nested `embedded_mtext` payload, which is snapshot-readable and preserved untouched. `staged_python_attribute_definition_lifecycle_over_real_ipc` passes C/R/E/D/U/I/V/P with a real block record, Block/BlockEnd markers and linked Insert: high-level creation inside the block, readback, grouped placement/default/rotation/width edits, selection, rendered text, atomic tag/height/style/owner rejection, deletion persistence, and three-step undo/redo. DWG reopens with the full edited state. DXF reopens identity, ownership, tag, prompt, value, placement, height and rotation, and OCS no longer double-converts ATTDEF/ATTRIB rotation. **W remains open:** acadrust `568a12c` dropped optional ATTDEF fields including width factor while reading DXF. Rerun the regression against the currently merged `7ea4247` revision and update this row with the result. `embedded_mtext` mutation remains unsupported pending linked-layout validation. |
 | AttributeEntity | **Complete** | OCS commit `cf2a9235` and adapter commit `9c6b5c3` make nested ATTRIB records addressable by handle while retaining canonical storage in `Insert.attributes`. Host validation binds tag to a definition in the Insert's block, validates placement/text geometry and style references, keeps owner and definition handles read-only, and preserves embedded MTEXT. `staged_python_attribute_entity_lifecycle_over_real_ipc` passes C/R/E/D/U/I/W/V/P with a real block, ATTDEF and Insert: high-level create/read/transaction edit/delete, parent selection, rendered text, atomic invalid tag/height/owner rejection, edited and deleted DWG/DXF reopen, and three-step undo/redo. `nested_insert_attribute_crud_uses_parent_storage_and_undo` additionally proves the child never becomes an orphan flat entity in the host document. |
 | Hatch | **Complete** | OCS commit `98b56ef6` and adapter commit `a9b5de8` expose solid and patterned Hatches with elevation/normal, complete pattern definitions, pattern controls, style, association state, boundary paths and seed points. Nested tagged boundary edges use the reusable `{kind, value}` adapter form. Host validation requires closed finite loops, validates line/arc/ellipse/polyline/spline payloads and stored pattern lines, resolves associative boundary handles, and preserves gradient and MPOLYGON payloads as explicitly unsupported. `staged_python_hatch_lifecycle_over_real_ipc` passes C/R/E/D/U/I/W/V/P: Python solid creation, patterned boundary edit, live render-model pattern/boundary checks, selection, atomic invalid scale/association/open-loop/unmapped-property rejection, edited and deleted DWG/DXF reopen, post-reopen edits, and three-step undo/redo. |
-| Leader | Layer-only | Requires annotation-linked fixture. |
+| Leader | **Integration-tested / blocked at W by acadrust** | Fields mapped writable: `vertices` (≥2 finite points, not all coincident), `annotation_handle`, `creation_type`, `path_type`, `dimension_style`, `arrow_enabled`, `hookline_enabled`, `hookline_direction`, `text_height`, `text_width`, `normal`, `horizontal_direction`, `block_offset`, `annotation_offset`. Read-only: `origin`, `dimension_gap`, `arrowhead_type`, `arrow_size`, `byblock_color`. Unmapped but preserved on edit: `override_color` (multi-payload `Color` enum the generator cannot express) and the `dwg_unknown_*` fields. Host reference binding validates that `annotation_handle` exists, is not the leader itself, matches `creation_type` (Text/MText, Tolerance, Insert; `NoAnnotation` forbids a handle) and that `dimension_style` exists; nothing is silently defaulted. `staged_python_leader_lifecycle_over_real_ipc` passes C/R/E/D/U/I/V/P against acadrust `7ea4247`: linked Text annotation, path/height/arrow/offset transaction edit with untouched-field preservation, GUI pick grouping (scripted selection stays exact), seven single-edit rejections plus a cross-entity atomic rollback, four-step undo/redo, real render linework, DWG and DXF reopen and re-edit. Erasing a leader also erases its annotation (scene leader grouping); undo restores both. **W blockers (engine, recorded as canary assertions in the test):** (1) the DXF writer never emits group 340, so a DXF save unlinks the annotation; (2) DXF reads drop `annotation_offset` (group 213 is written but not reassembled); (3) DWG R2010+ does not store `text_height`, `text_width` or `hookline_enabled` (acadrust writes them only for R13–R2007 / R13–R14). Not `Complete` until the engine round-trips (1) and (2); (3) needs a decision to document or make read-only. |
 | MLine | Layer-only | Requires valid style and vertex fixture. |
 | Dimension | Layer-only | Track individual dimension subtypes. |
 | MultiLeader | Layer-only | Requires nested context and style fixture. |